EGGP EGBK EGSC EGSR EGMC LFAT
Maybe this is what you have in mind.
It would be an easy route to plot on the map or GPS overhead a number of smaller airfields.
The route avoids class D so is all in open FIR so no hassle there - albeit a little tight around Stansted so stay a little more to the East. It also avoids any more tricky transits - you could save some time following the VFR corridor over Luton or going between Stansted and Luton, but more accurate navigation and / or clearances are required.
Finally you could route direct to Cap Gris Nez and then along the coast to LFAT if you want to minimise the time over water.
About 2 and half hours at typical Warrior speeds in zero wind.