Sorry for your loss Plumpie, its not good to have this unresolved after 3 years. Can we assume there was no will?
Do you still use the villa as much as you used to? If not then maybe its best to sell it and be free of the worry. Or if you want to keep it and buy the family out then I suggest its time to get a bit of legal advice yourself to help move things along. There are plenty and this is not a recommendation, just an example of the type of firm you should look for in your area.
http://www.sjstokersolicitors.co.uk