Am driving up to Powys from Salisbury and would like to break the journey somewhere to give the two toddlers a chance to run about and have lunch. Have been looking at service stations - which seem fairly dull on the whole, just wondering if any locals could recommend a play park or similar that's not too far from the motorway?
If you can hang on until J32 (am guessing you will want to join the A470 there), you can get off at Castell Coch - very, very close to the junction. Good cafe and grassy areas before paying (no play area though, and their "baby change facilities" are impossibly cramped. Better to use the grass...)
There is an indoor play place called whirlikidz (?) in Chepstow, just off M48 if you are going over the old Severn bridge which has a good reputation though haven't been myself. Can find link if you are interested
Oh PhD you're a wonder, sleep deprivation not an issue - Caldicot looks great, but we do have an archaeologist in our party so maybe Caerleon will win out. It's certainly ideally situated, am also chuckling at prospect of asking a local where The Ffwrwm is without laughing.