I spent a little bit of time looking at it and I can get it close - its not perfect but I hope it'll work for you as a placeholder until the next release. You should also be able to make tweaks to the positioning of the title, links etc if you need to move them a bit.
CUSTOM HTML
<div class="fg__header" style="background-color:#132f65;border-bottom:5px solid #132f65;display:flex;flex-direction:column;height:90px;line-height:90px;width:100vw;">
<div class="box" style="width:240px;">
<img src="https://images.static.shropshire.gov.uk/newshropshire/v2.0.2/img/sc-logo-swoosh-v1_250x80.svg" width="210" height="113">
</div>
<div>
<h2 style="color:#fff;height:90px;margin-left:1em;margin-top:.8em;text-align:left;width:calc(100vw - 240px - 220px);">
Map Gallery
</h2>
</div>
<div style="color:#FFFFFF;font-size:65%!important;margin-right:1em;margin-top:.8em;width:auto;">
<p style="text-align:right;">
<span style="color:hsl(40,94%,58%);"> </span><a href="https://gis.shropshire.gov.uk/resources/pdfs/AGOLhelpguide.pdf" target="_blank"><span style="color:hsl(40,94%,58%);">Help</span></a> <a href="https://gis.shropshire.gov.uk/resources/pdfs/Disclaimer.pdf" target="_blank"><span style="color:hsl(40,94%,58%);">Disclaimer</span></a> <a href="https://gis.shropshire.gov.uk/resources/pdfs/TermsAndConditions.pdf" target="_blank"><span style="color:hsl(40,94%,58%);">Data Use</span></a>
</p>
<p style="text-align:right;">
Contact: <a href="mailto:gis.support@shropshire.gov.uk?subject=Map Gallery Feedback"><span style="color:hsl(40,94%,58%);">Email</span></a> <a href="tel:+441743 258799"><span style="color:hsl(40,94%,58%);">01743 258799</span></a>
</p>
</div>
</div>
CUSTOM CSS ( I don't think I changed much here it's mostly your css)
:root {
--max-width: 1164px;
--focus: #ffdd00;
--primary: #003078;
--secondary: #266502;
--accent: #1d70b8;
--grey: #b1b4b6;
--light-grey: #f3f2f1;
--logo-width: 250px;
}
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@100..900&display=swap');
* {
box-sizing: border-box;
}
html {
font: 400 18px/1.25 Inter,Helvetica,Arial,sans-serif;
-webkit-font-smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;
text-rendering: optimizeLegibility;
}
@media (min-width: 1024px) {
html {
font-size: 18px;
}
}
body {
background-color: white;
color: black;
font: inherit;
}
a:link, a:visited {
color: var(--accent);
}
a:hover {
color: var(--primary);
text-decoration-thickness: max(3px, .1875rem, .12em);
text-decoration-skip-ink: none;
}
a:focus {
outline: 3px solid transparent;
background-color: var(--focus);
box-shadow: 0 -2px var(focus), 0 4px black;
text-decoration: none;
}
a:is(:active, :focus) {
color: black;
}
a > span[style*="color"] {
color: inherit !important;
}
a > img:only-child {
display: block;
}
p {
margin: 1em 0;
}
p:first-child {
margin-top: 0;
}
p:last-child {
margin-bottom: 0;
}
h1 {
margin: 0 0 1rem;
font-weight: 700;
font-size: 2rem;
}
h2 {
margin: 0 0 1rem;
font-weight: 700;
font-size: 1.5rem;
line-height:90px;
}
h3 {
margin: 0 0 1rem;
font-weight: 700;
font-size: 1.25rem;
}
h4, h5, h6 {
margin: 0 0 1rem;
font-weight: 700;
font-size: 1rem;
}
.fg__header {
color: white;
background-color: var(--primary);
padding: 0;
border-bottom: 10px solid var(--accent);
text-align: center;
}
.fg__header a:any-link:not(:focus) {
color: inherit;
}
.fg__header-title-section {
color: inherit;
max-width: var(--max-width);
margin: 0 auto;
padding: 0;
gap: 1rem;
display: flex;
flex-direction: column;
position: relative;
justify-content: space-between;
align-items: center;
}
.fg__header-title-section:before {
content: '';
display: block;
background: url('https://images.static.shropshire.gov.uk/newshropshire/v2.0.2/img/sc-logo-swoosh-v1_250x80.svg') no-repeat center center;
width: var(--logo-width);
aspect-ratio: 25/8;
margin-top: -1rem;
}
.fg__header-title > :where(h1, h2, h3, h4, h5, h6):only-child {
margin: 0;
}
.fg__header-title-info p {
display: flex;
flex-wrap: wrap;
gap: 0;
justify-content: center;
font-size: 0;
margin: 1rem 0;
}
@media (min-width: 900px) {
.fg__header-title-section {
flex-direction: row;
padding-left: calc(var(--logo-width) + 1rem);
}
.fg__header-title-section:before {
position: absolute;
left: 0;
}
.fg__header-title-info p {
justify-content: end;
}
}
.fg__header-title-info p:first-child {
margin-top: 0;
}
.fg__header-title-info p:last-child {
margin-bottom: 0;
}
.fg__header-title-info a {
display: inline-block;
font-size: 1rem;
word-wrap: anywhere;
}
.fg__header-title-info a:not(:first-of-type) {
margin-left: 0.5em;
}
.fg__header-title-info a > span {
display: contents;
}
.fg-search-area__container,
.fg-input__container,
.fg__filters,
.card-gc__info-row,
.card-gc__sub-container,
.card-gc__thumb-overlay,
.nav-pager__btn.nav-pager__btn--disabled {
display: none;
}
main.fg__body {
padding: 0 1rem;
}
#gallery {
max-width: var(--max-width);
margin: 1rem auto;
background: none;
padding: 0;
}
.fg-results__item-grid {
display: grid;
gap: 1rem;
grid-template-columns: 1fr;
grid-auto-rows: auto;
align-items: stretch;
margin: 0;
}
@media (min-width: 320px) {
.fg-results__item-grid {
grid-template-columns: repeat(auto-fit,minmax(calc(320px - 2rem), 1fr));
}
}
.card-gc__container {
margin: 0;
background-color: white;
border: 1px solid var(--grey);
border-left: 0;
padding: 0;
position: relative;
width: auto;
}
.card-gc__container:where(:hover, :focus-within) {
background-color: var(--light-grey);
}
.card-gc__container:focus-within {
outline: 5px solid var(--focus);
}
.card-gc__container:before {
content: '';
display: block;
position: absolute;
left: 0;
top: 0;
bottom: 0;
height: 100%;
width: 5px;
background-color: var(--accent);
z-index: 100;
}
.card-gc__thumb-container {
margin: 0;
padding: 0;
position: static;
background: none;
}
.card-gc__details-container {
min-height: 0;
}
.card-gc__details {
padding: 1rem;
display: block;
}
.card-gc__details *:where(h1, h2, h3, h4, h5, h6) {
margin: 0 0 1rem;
color: var(--accent);
}
.card-gc__thumb-link {
display: block;
}
.card-gc__thumb-link:before {
content: '';
display: block;
top: 0;
left: 0;
right: 0;
bottom: 0;
position: absolute;
z-index: 999;
}
.fg__wrapper > .nav-pager__container {
margin: 1rem 0 0;
list-style: none;
display: flex;
flex-wrap: wrap;
padding: 0;
}
.nav-pager__page-btn-container {
display: contents;
}
.nav-pager__btn {
padding: 0.5rem 0.85rem;
display: inline-flex;
gap: 0.5rem;
align-items: center;
}
.nav-pager__btn:is(#previous, #next) {
font-weight: 700;
}
.nav-pager__btn:not(.nav-pager__page-btn--active):hover {
background-color: var(--light-grey);
}
.nav-pager__page-btn--active {
background-color: var(--accent);
color: white;
}
@supports (---icon: url(data:)) and ((mask: url(data:)) or (-webkit-mask: url(data:))) {
.nav-pager__btn#previous {
padding-left: 0;
}
.nav-pager__btn#next {
padding-right: 0;
}
.nav-pager__btn#previous:before,
.nav-pager__btn#next:after {
content: '';
display: block;
height: 0.85rem;
width: 0.85rem;
background-color: var(--grey);
}
.nav-pager__btn#previous:before {
---arrow-left: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 15 13'%3E%3Cpath d='m6.5938-0.0078125-6.7266 6.7266 6.7441 6.4062 1.377-1.449-4.1856-3.9768h12.896v-2h-12.984l4.2931-4.293-1.414-1.414z'%3E%3C/path%3E%3C/svg%3E");
-webkit-mask: var(---arrow-left) no-repeat center center;
-webkit-mask-size: contain;
mask: var(---arrow-left) no-repeat center center;
mask-size: contain;
}
.nav-pager__btn#next:after {
---arrow-right: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 15 13'%3E%3Cpath d='m8.107-0.0078125-1.4136 1.414 4.2926 4.293h-12.986v2h12.896l-4.1855 3.9766 1.377 1.4492 6.7441-6.4062-6.7246-6.7266z'%3E%3C/path%3E%3C/svg%3E");
-webkit-mask: var(---arrow-right) no-repeat center center;
-webkit-mask-size: contain;
mask: var(---arrow-right) no-repeat center center;
mask-size: contain;
}
.nav-pager__btn:focus:before,
.nav-pager__btn:focus:after {
background-color: currentColor;
}
}
.fg__header, .custom-header, .custom-inner-header {
display:flex;
width:100vw;
padding:0;
}