Also AA website is good for advice.
The most important thing is if you have a heavy right foot take a heavy wallet - the cops in France fine you cash on the spot, although I have not tested this theory personallement.
Check with insurance co if covered for continent -
Don't forget your headlamp converters, but check in your manual first, cos some newer models you just flick a switch and they are converted.
GB badges, fire extinguishers maybe, first aid kit, spare lamp kit and if you goto Greece (seriously!) take a pair of spare plates cos if you park illegally, the cops nick your plates!! Really!!
Need D L, V5, Insurance Docs - It is a PIA, but copies are no good.
And if you are stopped, don't turn to the missus and say "Can't get the hang of this Brummie accent luv, can you?"