I guessed as much. Unfortunately co habitation/trust disputes are the "new divorce". Sorry, I meant declaration of trust (I tend to forget not to talk "legal").
If you can find a solicitor specialising in trusts of land (ToLATA)/co habitation disputes so much the better. However a decent sized firm with a private client department should be able to provide someone to help. Some family lawyers are now developing into this area too.
To give you a basic idea of how it works is that as she is not on the title and there is no trust deed she has to prove that they intended to own the property either a) jointly as equal partners or b) jointly in the respective shares of their contributions. Unless the �76k was a gift (extremely unlikely), she should not have a problem doing this - b) is the most likely outcome.
As she has moved out, as part of her claim, she will also need to include a claim for occupational rent for "her" share of the property that he is living in.