I'm in France in a couple of weeks and it just so happens that there is a RAID VTT in the forest where we are staying. Are these events like UK marathons or XC races?

Try looking here

Accueil

no, they will be much more fun than that

If you send me the link about the raid I may be able to help

There is no link to the event as such. I just spotted a little bit of info on the local Mairies website: here

where abouts are you going??

The thing on the marie's site talks about a "Raid Aventure", so not specifically biking.

A raid generally is a multi-day trip, but it is quite often used for races as well.

in the Haute Vienne alot of villages have a "Randonne" route board with waymarked routes on them

It says Raid Aventure, and it's run by the ASSCI

It's €15 to enter, and its a MTB orienteering event.

The info is here.

More here.

HTH
SB

ah ok. Not quite what I was expecting. Thought it might be a marathon.
Looks like a team event anyway and I have no experience of orienteering either.
Bum.