We go for BTCC. Campsite is great at Oulton. You camp right next to the track. I seem to recall that you can camp in any type of unit, caravans, campers etc.
Have camped at other circuits but Oulton is the best in my book.
We have just booked camping for the BTCC the weekend after next... Can't wait, but there is precious little information about the site on their website... Bit worried there will be no facilities at all
There are showers and proper flushing toilets. These are in portacabins close to the entrance to the site. They are cleaned during the weekend but I have found their cleanliness to be variable. Make sure you take your own supply of toilet paper and you will be fine (toilet paper was available most times but I like to be sure!)
There are also portaloos in the camping field and water points.
You have to expect that facilities at events like this are not going to be like a campsite. There is no wash up facility and the tents can be quite closely pitched.
Also late night noise can be a problem. Last year I had to ask some neighbouring campers to reduce the volume of their heavy bass beat tunes when it got to 00.30. They didnt cause any problem but then very kindly left some earplugs on my chair the next day!
All that said, it is still one of my favorite camps of the year.