I can't contribute as not having been in a similar plight but reading your post I think your mind is already made up in favour of France and perhaps you seek confirmation of that?
Keeping your other half happy is important and as you both get older and spend more time with each other that's a key consideration. If you went UK and she hated it then it might lead to other problems.
Trust your gut feel, me sitting here in miserable UK weather creates a bias.. And as others have said its only a hop away
Steve it is almost made up in favour of France and and there is no plan that can't be changed should circumstances change. What might make the difference, whichever way we decide, is the ability to go to Australia (once fully retired) for a significant part of the European winter. That would get me through. But then comes the day when one loses the energy or ability to keep doing that. Just thinking out loud. And you're absolutely right that if the other half is not happy then we are definitely in the wrong place.
