hello
@Fiomcirv
welcome from me too
I wonder how your dad feels about moving, as he is the one who is his wife's main carer - would he like to move to be near you all or prefer to stay in the location he knows - he needs to be able to have some time to himself and may want to visit his friends or he may be happier knowing you are available to support him and he can make 'dates' to see his friends
maybe you could look into care homes (who accept residents with dementia) near you so that if they move and your mum eventually needs to move into a home, there is at least one suitable home within easy visiting distance (and consider putting your mum's name on a waiting list)
there's the expense to consider too, it takes £1000s to move and time
if they go ahead, maybe your mum could have a respite stay for a week so she sees nothing of the messy part of moving, and have everything packed by professionals as your dad will be very stressed, indeed could he have a break too?
also, be brutally honest with yourself, how often will you really visit and how much actual physical support are you willing and able to provide, taking into account that your parents may expect much more than you can offer
your mum may well be believing that moving back to her familar stomping ground will effectively take her back to how she was then, which we know cannot happen, but then she will probably feel the same wherever she lives