American RV use in the UK

What is the Caravan Club policy on American RV use? Do any Caravan Club sites have RV dump stations where the onboard black water tank can be pumped clean? 

My wife an I currently tow a caravan but are giving serious thought to buying an older (much older) American RV but are worried that facilities on UK sites are not suitable for the regular use of RV's. Do any of you more experienced RVers have any comments please?