french connection

Wanted some advice really.  My mother lives in France but, following the death of my father last year, now wants to return to the U.K. to live.  Unfortunately she is unable to sell her French house at the moment, as it has subsidence caused by clay soil and very hot summers and she is waiting for the Government to pay compensation for the works.   So she is looking at renting out her place as a holiday let.  Please can anyone let me know how this works in a legal sense and from a taxation perspective.  Also any tips and experiences from those who live in the U.K. and do holiday lets on your properties. Many thanks