Further to our updates on the closure of the road at Tintern.
I can tell you as a keen cyclist that their is indeed a route up from Tintern Valley to St Arvans near Chepstow. which i have been using regularly while the road is closed.
Turn right by the Abbey itself head up that road and stay left climbing up through the lane to bring you out at Eagles nest car park from their you are on the road past Chepstow Racecourse into the town of Chepstow.
Everyone misses it because its a lane not a road and its signposted closed at the moment.
you can actually get a vehicle up through it buts it not easy as its so steep and narrow.
Its pretty steep mind you and not for the faint-hearted also its more of a track than a road so be warned if you need to un-clip to allow a vehicle to get past, although you won't see many its not an easy task.