Rudding Holiday Park looks great for families.
I found it, and many other possibilities, by going here:
http://www.yorkshirevisitor.com/
The search criteria I used were 'Caravan & Camping Parks' within 30 miles of Ripon.
There were 44 results. Although some of these are only caravan parks, there are plenty of campsites listed as well. Rudding Holiday Park accepts tents (as well as caravans) and has all the facilities which a family might want. It's 11.5 miles from Ripon.
Chris