This place used to be a caravan park, but now it isn't. I didn't realise what it was until I got home and spent ages researching it - there was actually something a bit military or health service about the land, with the signs for 'fire point' and the clinical white and green railings. I probably should have guessed - after all, there were a bunch of caravan sized concrete slabs all over the place, but I wouldn't have been surprised if it had turned out they were foundations for WWII huts. No idea when the main house was built, and no idea when it closed - looks like it's been empty for many years, but Google Maps shows it with real life holidaymakers on site.
Anyway, I couldn't get in the main building, it was sealed shut. Might be just as well - who wants to go wandering around an abandoned caravan park reception building? Not me, no thanks.