The slope wasn't that bad, I put it down to the air bed being shinny it's a airobed explorer, so I'm going to get a fleece sheet for it and see if it helps in the future as well as keeping us extra warm.
We too had the same problem at Lime Tree Park a couple of years ago, but we just moved the airbed around to that shoulders were uphill, feet downhill (suppose it depends if your tent can accomodate this tho!). Didn't let it spoil our trip and would definitely go there again.
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.