OBK, try using the Pooleys & Jeppessen guides, page 8 of the 2002 Pooleys states that a flight plan must be filled for all SVFR flights in the Channel Islands CTR.
As the Channel Island CTR is Class A, you must flight plan, then as they expect you a SVFR clearance will be given to you (radio just before 50N). Unless you are on an IFR flight plan.
The AC must be equiped with the appropriate transponder equipment. (Pooleys)
Do not fly below 2000ft AGL within 3NM of Sark. (Pooleys)
Other things are mentioned, but i'm not going to type the 2 pages.
Pooleys again, page 657, there are 33 designated airports in the UK, Bristol, Bournemouth, Exeter, Lydd, Plymouth & Southampton are there. You can go dct, but PPR from your local Chief Constable is required in writing.
Upon arrival you must fill out a gendec for the Jersey authorities.
If your twin is 3 tonne or under you will be processed by the Aeroclub, a good set up, you can have a beer upstairs and then go to wherever you are going. The fees are £3 per 1/2 tonne & free parking up to 7 days, grass parking. The club is at the threshold end of RWY27.
If needed the aeroclub can help with accommodation & taxis or car hire.
Have a good trip.
FB