How about
15th to 16th July Folk among the Roses at Nature's World, Middlesbrough
20th - 24th July, yes it starts on the Thursday, Staithes Acoustic Weekend
28th - 30th, last but not least, Durham Folk Party
the last 2 have camping for £4/5 per night

By the way just a 'plug' Denaby's £5 per night for a tent as long as they havn't increased the campsite prices