+ done this on 3 occasions myself.. flying to the uk is easy peasy, then missing train because flight delayedmissing ferry at dover because of traffic etc..its rough
but fun and always a good laugh.
the OP needs to tell the french buyer to sort out 1 day insurance cover and arrange his insurance for when landing in calais
haha sounds like it was smooth sailing for you then I will tell him to get the insurance sorted, He's getting in touch on sat to get things arranged (Hopefully) so I'll make sure all is safe and legal to get him back home with out the fuzz chasing him