Matt,
Thanks for your reply. As suggested I exported the cutline file to a new one. Then I tried setting all the attribute data to "null" using the field calculator. I ran the GeoRAS process for attributing Station, Banks, lengths and heights etc. and all seemed to work OK this time, it went past the previous xs that were in order to include the new ones added at the end. Not sure if it was exporting to a new file or clearing all the previous attribute data, but luckily I did not have to resort to recreating the mxd or have to draw my 1500 cross sections again.
I agree that GeoRAS does have some odd and annoying quirks!
Thanks again for your assistance
Tim