Thanks for the comments and help. I can confirm it is projected in WGS84. The Co-ordinates are in decimal degrees, and include a negative latitude. The co-ordinates are all in the region of 53 (longitude) and -8 (latitude) which would be correct for Ireland. In order to make sure its not picking up any issues from a projection system on a different co-ordinate system I've projected them on the OpenStreet Map basemap which as far as I'm aware uses WGS84. The units of the data view are in meters. I've checked the data frame extent and it appears to be set at 0. Below is a screen shot of the layer properties.
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