I'm sure you'll find some French pilots with loads of advice.
Just one hint from me, though, to add to whatever advice you find elsewhere. French charts don't show airways with a base below FL65. In the UK, there are Class A airways with their base well below this level. So if you want to avoid infringing the airway, it's essential that you buy either a UK chart or a Jeppesen chart, even if your French chart covers the entire area you'll be flying in. Particularly important if you're flying around the Isle of Wight/Southampton/Bournemouth area.
Good luck, and enjoy your trip!
FFF
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