As well as crusing trhe area I do deliveries from the MED to the UK (and other places).
Buy the French charts FROM any newsagent in FRANCE - they are much much better that the UK ones and a lot cheaper. There are several types and most have one chart on one side and a second chart on the other side. Once you get used to them they are great.
I have to admit that I use the IMRAY biscay passage chart for PASSAGE planning and plotting each time I cross.
Although if you have time crusing round the insode of BISACY is fantastic - there are lots of great places to visit and hundreds of good anchorages. Only problem are the firing ranges near the French/Spanish border (look in reeds for details) as you can only realistically transit these at night. it's not difficult just a pain!