Not quite Tenby but saw your previous post asking for similar info relating to pembrokeshire generally.
Have you thought of Newgale? Beach across the road and pub serving food next to site.
Showers etc clean. They charge £5 per person per night (adults and children same price). Tent size not a problem - anything goes here. BUT no marked pitches - it's pitch where you like. Haphazard but friendly site.
You can't book though - first come first served. We're regular visitors and this is generally not a problem. However, if you intend to arrive on the Friday before August bank holiday you need to get there early. The site tends to attract weekend campers so always space if you arrive on a weekday even in peak periods.
HI anallew. We have actually got somewhere booked now. It`s at Manorbier and is now known as Buttyland! I believe it is near to Manorbier Country Park. Your site sounds nice but at £20 a night for all four of us is a bit more than I want to pay.
We stayed at Windmills Which is pretty much right in the middle of Tenby and Saundersfoot. Quiet site and happy to take a large trailer tent. There are loads of sites in the area, so you shouldn't have a problem finding one, even if you don't book.
Don't forget to leave a review of the campsites you have visited this year or last!