In chronological order

Great Alne, Warwickshire. 
End of April. A small international dance festival in the village hall, www.greatalnefolk.org.uk
In the countryside East of Alcester. Close enough to travel there from home.

Chippenham Wiltshire.
Spring Bank Holiday. One of our favourite festivals as it has a variety of dance workshops and concertswww.chippfolk.co.uk. The campsite is next to the Avon, about 1/4 mile from the town centre, where all the events are.

Lichfield, Staffordshire.
Mid June. Mainly dancing, based in Bader Hall, to the East of the city centre. www.lichfieldfolkfestival.co.uk
Space just for caravans and campervans (but close enough to travel there from home).

Warwick, Warwickshire
End of July. A lovely site in an Eastern edge-of-town private school. Luxury theatre, swimming pool, level grass, Little dancing but good concerts & displays www.warwickfolkfestival.co.uk

Sidmouth, Devon
First Week in August. We’ve been to every Sidmouth Folk Festival Week since 1988. This was a big international festival, 2004 was the 50th, there was a scaled down one in 2005. it is growing back up again. A wide variety of dancing plus many concerts, about 70 events a day. The campsite is on a sloping cattle field on the edge of town, about 1.5 miles inland of the sea front. Venues all around the town.
www.sidmouthfolkweek.co.uk/ and www.See Red.co.uk

Shrewsbury Shropshire.
August Bank Holiday. (Used to be in Bridgenorth, Moved to Shrewsbury in 2006). On the West Midlands Showground, next to the River Severn 1/2 mile west of town centre. Little dancing but good concerts & displays. Level on-site camping, some permanent facilities, 2,000 seater main marquee.
www.shrewsburyfolkfestival.co.uk/

Bromyard, Herefordshire.
Edge-of town field, dancing in town on Sarturday. Another of our favourites, good concerts, dances, and displays. www.bromyard-folk-festival.org.uk/

Bedworth, Warwickshire.
We hadn’t missed Bedworth since the first one we went to in 1985 until 2012: when we stopped going.  We used to enjoy the dance workshops but now it’s just concerts. www.bedworth-festival.info/

We camp at all the festivals May to September as all we need is somewhere to sleep and these festivals have camping sites.

There’s also:
Mosely Folk Festival. Birmingham. www.moseleyfolk.co.uk/
First weekend in September. Open-air in an attractive private park. I was excited at having a folk festival 20 minutes bike ride from home. I went there on the Friday in 2008 but I won’t go there again for four reasons:
1. They didn’t let me take in a can of larger to have with my picnic (the only time I’ve been searched on my way onto a festival site)
2.  Many smoked (not just tobacco): on a windless evening the smoke hung in the sheltered park (I suppose smokers were attracted to an open-air venue).
3. There was an area for sitting on the grass, in front of one for sitting on your own chair. A few started standing in the sitting area, others soon copied; soon everyone had to stand to see.
4. There was much talking, I estimated that half the audience were in a conversation – disrespectful of the performers and audience.
Is it relevant that there were many more people in their 20’s than at other festivals I have been to?