Hail large enough to damage cars is getting quite common in parts of europe and some countries actually launch missiles that seed the air with aluminium dust, which causes the hail to form in smaller sizes.
Personally I would get quotes locally from independent body shops who may be more experienced than uk body shops in costing , and repairing, this kind of damage You may find local UK 'ex pat' forums can recommend good places.Possibly better info than finding recommendations back in the uk.
Even if its a bit more than your 'excess ' It may be preferable to persuading uk insurers that damage caused months previously in France is covered,(if indeed it is covered ) and having to pay any excess, and possibly losing some no claims bonus. And look on the bright side. Its your decision, with no other driver or his insurer involved
Bear in mind also that if you contact your UK insurers enquiring whether such and such damage is worth claiming on insurance or not they may well record it as a 'claim' even if you decide not to make a claim. You would be regarded as a higher risk because you experienced damage. It probably wouldnt affect your no claimms bonus directly but they might actually increase your premium at the next renewal quote, with you being none the wiser that its higher than it would otherwise have been. And same applies if you get quotes elsewhere - they share info.
If the local quotes are so high its obviously going to be an insurance claim its probably best to inform your insurance company immediately, rather than when you get back. I believe they often check metrological records for damaging storms,so honesty is the best policy with regard to dates.
