Wow. There are actually places in the UK where a motorhome is welcome!! Most requiring payment, of course.
This reminds me of why I now live in France!
Here in Brittany must be the most Camping Car friendly place on earth. Camping Cars are allowed by law to spend one night in any public place where they are not causing a nuisance or obstruction. And no payment is asked for.

I have spent nights in town centre car parks in France - very convenient. Imagine that in the UK? Hmmm....
Aires on Motorways and other major roads (provided for the safety and convenience of the taxpayers who pay for them) are free and most have basic facilities for Camping Cars.
Most villages provide dedicated parking places with facilities which are free of charge (some with electric hook-up for a couple of Euro per day).
The most scandalous thing in the UK is the charging of parking fees at Motorway services. At night the car parks are all but deserted, HGVs and Camping Cars being consigned to the unsafe lay-bys. I do not know why the Government is allowed to get away with this. They have hived off the running of the car parks (the collecting of fees) to private companies. The car parks were built using Taxpayer's funds and are maintained by the taxpayer. Why is it necessary to employ a company to charge parking fees? Hardly anyone pays, of course. And where is the safety aspect? After arriving on a ferry from overseas, a visitor may not understand the signs showing the time limits and charges, and park up and fall asleep. When he wakes he is likely to find that he has been clamped and has a big bill and a lot of hassle to get going again.
Only in the UK, eh?