I have just emailed a friend of mine who lives in Marloes asking for a review if I know him it will be a couple of days before I hear back, as soon as I do I shall post here.
Just come back from this site - very impressed with it. Good clean toilets (and the rolls never ran out!). Clean showers (2 of them - 50p a pop) and good washing up facilities. The site is tidy, quiet and well run by the owners who were very helpful and polite. Ideal location for day trips to Skomer or the numerous sandy/rock pool beaches within walking (or short drive) distance - 8/10.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.