Potential TOLATA claim

So Decree Absolute granted over 7 years ago but ex did not engage or correspond through whole proceedings so no financial order at the time. Ex has remarrried which bars them from claiming under matrimonial law but is threatening TOLATA claim for beneficial interest in former matrimonial home which is in my sole name and also on deeds, mortgage etc. House is new build which is incomplete and not signed off as ex left before it was finished and has not contributed a penny since, leaving me to continue to carry out works and repairs and yet is trying to claim beneficial
interest. House can't be sold as not signed off. Ex was and continues to be financially irresponsible and is going from place to place incurring debts, they left owing thousands to local trades people. How do I stand and what is best way forward. Only one seperate jointly owned small asset to play with.