Gifted Property- Family Dispute

[Loski_2018]

Hello, I'm looking for some advice if possible.To provide a bit of background, I was raised by my Grandmother since birth and then also her 2nd husband since I was 4 years old. (She remarried after my Grandad passed away) The reason she raised me was I came from an unstable violent home so she provided me with a safe/stable place to live. Fast forward 30 years and the property (my childhood home) which I moved out of at 18 was decided to be gifted to me mortgage free as a nest egg for my later years. The property was always in her husbands name,mortgage and deeds however I believe my grandmother may have made payments towards it at some points. In 2016 my Nans husband gifted the property to me whilst they both continued to live there. My grandmother has sadly recently passed away and now her children are disputing the property ownership. Her husband still lives at the property and will continue to do so until he passes. I am hoping to understand if the property ownership can be contested in anyway. It was not held in joint tenancy, it was solely in his name and she died with no will. Any advice would be greatly appreciated. Thanks.