Hi, and sorry to hear of your predicament.
To get meaningful and sensible advice you'll need to provide more details. For instance, was the loan taken out with a French or a British bank? Was it secured against your property? You say you use the property for gite holidays - do you run these through a business, and if so is the property in the business's name, or your own?
The impression I have is that declaring personal bankruptcy in the UK is a pretty miserable affair with lasting effects. I don't know how it is in France.
But this sounds like the sort of question for which you really need professional financial advice - which unfortunately we're not qualified to offer.