I have been to Clumber a few times, the NT one not the CC one. I didn't mention it as I thought that might be a bit too far for you OP.
Is nice, simple camping. No EHU, just a big flat field. They used to only pitch round the sides of the field, if they still do that it will be nice. If they try to cram in more tents in the middle it wouldn't be such a nice place (saw a photo showing just that).
There are three loos and showers in the ladies, not sure how they do it but there is never a queue and they are always clean. The people who run it (if they haven't changed) are lovely.
You get access to Clumber Park too, including after the gates go down, lovely to walk to the Lake in the evening. We did a night time walk in the dark in our pyjamas the year it first opened.
Good for bikes - but they have had a bit of a bike theft problem and have been a bit naughty by not making campers aware - very clued up bike thieves apparently
.
You do have to pay a deposit for a card to get in and out but we have never done that as we have biked/walked while we are there.
The NT cafe is nice, opens for breakfast and stays open til 5:30 ... and you can buy wine and ice-cream if you are desperate!