Has nobody thought of advising you to obtain an order of court giving you the sole power to sell the property.(posted 7403 days ago)A solicitor should be able to advise on this method. As to service of any proceedings on your other former half, this an be done, again by order of court, through newspaper adverts - called substituted service.
Even if this method did cost you a few bob, it will be a lot better than the loss you will sustain if you allow the property to be repossessed and eventually sold for peanuts - you might even end up with a shortfall!!!!!!