It may sound crazy, but there are lots of rocky forested hills in the Ardennes, just back and followed some VTT routes, fine singletrack in places, but very much in the old school xc style, with loads of rutted logging roads, anyone got any experiences, recommendations for good trails, just in case we head back.

Only done one in the Moselle region. Pretty easy, family friendly, just get out and ride type rides, with ice-cream by the river on the way back. Well signed too (just 1 sign missing in the middle of a forest). PDF routes for those are on the visitluxembourg website.

Would possibly consider linking in with something on the German side of the river, which is a bit hillier and more forested.

Have a booklet for the Ardennes ones but never got around to actually riding any. Probably a bit more interesting there? Less vineyards and more hills?

Yep more hills, some pretty steep climbs in places, one loop at berdorf started promisingly with an amazing descent down a gorge/gully, to a nice singletrack climb up to beaufort, after that it all became a little tedious with miles of logging roads.

Interesting-thought of heading for the Larochette area sometime so will take note of any routes too.