You can fly direct if you are happy with 75nm across water.
Otherwise I suggest flying Wickenby, Fenland, Earls Colne, Southend, Dover Calais and then up the coast to Ostende. This is ~50nm further but only 20nm over water.
Most of the route I have suggested is uncontrolled. I generally prefer to route from one airfield to another. Then if the weather turns bad you only have a short retracing of your route.
Many airfields will do all the GAR and flight plan filing for you for a small fee I'm sure Sherburn will do it, and even if you want to do it yourself, I would suggest giving them a call. You could always use Earles Colne or somewhere else en route. Southend can do it but they charge a lot.
If you decide where you'd like to stop then give them a call. Generally they need at least 24 hrs notice and the names and passport numbers.
Also stopping somewhere down south will mean you can refuel and then not have to pay the much higher price for Avgas in Ostende.
Its a nice easy flight. about 200nm direct or 250nm via Dover.