If you look at the top of the page, there is a facility where you can search for campsites. If you look for North Devon, there are 3 pages with sites there, not all in the area you are looking for, but there are some. Damage Barton for one, is a really nice site in my opinion.
A day of all things motorhome and campervan. The show is held both in the main indoor arena and across the grounds. Catering, hot drinks and food options are available. Easy access to the site and free parking included. Win one of five pairs of day tickets