Why would you go Dover Calais?
Much better go Lydd L2K direct or even coast in a little to the east of L2K if you want to shorten the crossing. In reality the difference between the two is so little as to make no difference.
If you go via Lydd you can talk to Lydd who will ask you to report 10 nm south, and if you are going to L2K you can switch direct to L2K and not bother with Lille.
If you route down Mig alley (rather than to the North of London) you can stay with Farnborough pretty much all the way to Lydd and get a traffic service from them.
If you route North of London they will take you from the Thames down to Lydd.
You can over fly the power station at Lydd above 3,500 but check the danger areas are cold (Lydd will tell you) or transit above 4,000 if you want to go over the top.
It is easy to avoid the lot if you wish.
Worth taking note of the shipping lanes if it is your first time. It is interesting to see the line of ships going into the North sea on the UK side and the line Atlantic bound on the French side. Distinct lanes, distinct directions.
Enjoy.