Allegedly, several times - a C152/C172 from Shoreham (think it might have been G-TOON?) about 1980, a Dan-Air pilot if I recall - this might be the same event as Jabberwok's post; then again... I do recall a friend from Dan-Air telling me some rumour or tother about it, but it's a quarter of a century ago!
There was a well known aviator who was lost in his beloved Tiger Moth crossing the channel several years ago, amid much speculation... an article about him appeared in the Telegraph magazine a few months later, though I can't remember any details as to why it was thought suspicious.
Some wreckage from the Cessna was recovered off the Channel Islands as I recall; no trace of the Tiger nor either pilot. To be honest, I think both simply crashed rather than doing a Reggie Perrin...