towing dolly
I have one. Its at presnt in North Kent, 2 minutes off the M26, should pass me by if your crossing at Dover. There is a problem. French law, if they stop you, require the dolly to be braked. Mine isn't at the moment, but I am intending to replace the tow hitch with a braked one off a caravan. You have to, or appear to have done so, attach a lever behind the tow hitch by cable to the handbrake mechanism. Should be easy on a Renault 4, but as long as you have the mechanism sort of attached, I doubt your average french plod, or Le Flic, will bother to get on his hands and knees to check it. Also as the quatrelle is held in huge affection by the french generally, I doubt very much that anyone will trouble you. Regards payment, not bothered.
Regards Tim