We used to go there every summer Saturday in a PA28 to clear customs to Le Touquet for lunch, having got a SVFR more or less direct across LHR, then call back in for inward customs.
Now I go as a passenger in airline aircraft and get nostalgic when I pick out the lake and rail line we used to use as inbound guides.
The world changes, and as Kirsty quotes, so do the costs and the welcome you are likely to get.
Another thought, suppose you get in, then fail the medical? Parking charges are probably sky high.