A note for future lejog people, once you turn off the main road after Tintern, the wee roads are somewhat confusing. i missed the first turnoff because it looked like someone’s driveway. Then i got very confused as to where i was and had to plump for carrying on up and down hills in the hope i’d hit the main b road. which, i eventually did.
Turns out, Google Maps satellite view is great for revisiting and analysing your mistakes!