Puzzling route in France

[Speedbird744]

Hello,

I am planning a leg from an island just south west of Nantes, Ile D'Yeu (LFEY) and hoping to fly DCT to the Scilly Isles (EGHE).
I am flying VFR and will depart on a weekday (when danger areas are most likely active).

I have checked this route and the first problem I find is that there is a section of the UK CAA Chart and the French ICAO chart that is missing part of the route just North of Brest.
I am assuming that the only thing that lies in that area of the English Channel is D18B and D18A?

Does France have a DACS like the UK that enables a pilot to transit D18B even when active?

How else would you fly this route if Brest Information tells you this danger area is active?
It would mean re-routing all the way, and how frustrating would that be!
And how exactly do you file your flight plan once airborne with Brest Information or Nantes Info?

Thanks very much

S744