We left the UK many years ago but we used to belong to a Caravan Club and as farmers we were allowed up to 6 caravans (bumper pulls/trailers) during the summer months of May through to September.   That was a lot of years ago though and am not sure if this is still in effect, although quite probable as staying on Farms in Cornwall, Devon, Somerset, Wales, Yorkshire Dales, Scottish Highlands, and many of the attraction areas such as Dartmoor, Exmoor, New Forest, (too numerous to mention all) is a very very popular thing with brits from big cities.   In addition there are a lot of "CARAVAN SITES", as we termed CG's years ago over there.

Check out:   Caranvsitefinders.co.uk   UKCampsite.co.uk     Caravancampingsites.co.uk   UKParks.com as a start might give you some ideas.

You will likely find that the costs are a far cry for what you get than here.   We noticed tons of Caravan Sites when we were in the UK touring for 11 days last month down both coasts, as well same noticed in N. Ireland and Eire = far more than ever I remember when we lived there, so it appears to be a very popular thing again of late, just as it did in the 70's then died away as cheap trips from the UK to Spain, Greece, Ibiza and many other islands became the flavour in the 80s,& 90's due to guaranteed weather many felt and cheapness was most comments heard.

Hope the above helps somewhat.   Also do your googling using www.google.co.uk  not .com to get maybe better results.

Enjoy, it's a wonderful country to vacation in.   France and some other European countries actually have places to boondock and encourage it, but that doesn't seem as readily accessible to know where in UK.

TXRVr, generally the cost of renting RV's over there we have found very high, not sure about the cost of RV Sites. The cost of houses have gone up exponentially in the SW I noticed, as upcountry folks have moved down in the past couple decades to escape the "rat race" for want of a better term. Supply and demand in an area that had no other economy after the mines closed down, other than selling ice cream cones (cornets in the UK!) for 6 months of the year or emptying bed pans for 12 months of the year. Interesting to see how things have changed with folks upcountry now coming down to live the "simple life" producing off the land with their monies earned elsewhere. The deep SW is still a retirement and vacational attraction area, so you will see many rental properties at much higher rates during peak time, and a lot lower rates out of main season, when they are targeting longer term local renters than vacationers for 6 to 8 month periods ideally.

Generally I have found even with the exchange rates of $'s to UK pounds (in our case 2:1), that with research you can still get on par or even a little cheaper hotels/property rentals and food a lot cheaper than on this side of the pond (albeit food has gone up as it has everywhere it seems in recent years). Fuel (petrol) is considerably more expensive, eating out used to be a lot more expensive than NA but in recent years seems to have come into line. Transportation ie; London Underground (Oyster card) was a good bang for our buck we felt maxed out on and off all day at around C$13, with a refund of unused portion and return of the card. Parking in car parks at the top of the hills, of what used to be working/living fishing villages in Somerset/Devon/Cornwall blew our minds, and even the businesses are bitter about how they've been privatised by one individual charging what they want = they say they get less tourists now than in the 70s because of it. Now all turned into tourist traps not allowing one to drive and park on the street as we were used to, albeit quaint and beautiful, but UK3 for 4 hours or UK4 for 3 hours = adds up when you are driving up and down the coast and only spending a half hour or hour max look see. One day it cost us over C$50 just in parking fees = now that's crazy in my book, but also maybe because generations of my family lived those areas and I'm just not used to being monetized to death in our previous lives there.

London hotel rates we found unbelievable and would never pay those rates in our usual travels - so that shocked us. For our 11 day stay of which we paid for 6 nights in hotels, car hire and very careful eating out, knowing what to get and where for best value, it cost us with our flights, train travel, gasoline etc C$5000. We didn't pay any admissions to any attractions. Just to give you an idea, and I am very frugal on how we spend our monies, buying supermarket goods to eat versus restaurants for the most part.

Anything I can help with don't hesitate to ask. From a tourist point of view for sure it is a very very beautiful country as are the folks you meet in the small quaint villages that have time to pass during the day with you - cities OTOH, your mileage varies somewhat in that regards from very friendly to comments from some of downright rudeness. Guess its the same the world over. All brits that have come to Canada (I did immigration for 14+ years) have commented to me "OMG, how friendly and helpful folks were, even in the city when they were seen looking at maps, offering help".

Have an organized plan, to embrace all that you can for as long a stay as you can and it will go down into your memory box as a truly wonderful experience I have no doubt.