Do we have a title plan with clear boundaries?

Our buyers solicitors are refusing to complete without sight of a title plan which shows a clear red boundary. Would our property have one? All I can find online is a registry general map which outlines 4 houses grouped together so I can see the confusion. House was built in mid to late 1930s

Aimee - that is an image of the title plan showing the land/property that was originally registered under the one title but since removed. There won't be another version 
A buyer is asked to compare the title plan with the reality on the ground and confirm if the sale details match what the title plan shows. The title plan clearly, for me at least, shows the extent of the one remaining property, so the red outlines less the parts edged and numbered in green. I can understand the confusion this may cause but it should be clear enough for them to make the match/confirmation
If not then their conveyancer can assist/advise