Update, since I know you’re all keen to know:
We went to Tenby beach, that was sodding freezing; St Davids (also cold); West Williamston nature reserve; Manorbier beach (more sheltered and less windy, a fun day) and then Barafundle (also sheltered and fun).
Just a couple of hours digging and rockpooling each time. The ‘van was good, side dinette layout surprisingly much better than I was expecting. Very well ventilated which made it pretty damn cold at night, but managed in the end. Most of it worked ok but one of the legs is trying to punch its way through the floor in the leaking corner 🙁
Site was good, v quiet and out of the way, nice views of the water, a bit windy though.