There are quite a few companies out there, don't forget breakdown cover as well. When you get to the Algarve there are plenty of campsites ranging from glorified parking lots to full campsites. Winter prices are reasonable. There are also plenty of wild camping sites though you may get moved on from some. Get to know people and there is a fund of local knowledge on places, where to eat, shop and get services.

Comfort is the one I use have done for last three years, tried others always the cheapest ,Saga was cheap first year then on renewal price shot up ,remember to check for windscreen cover some policies don't cover the cost of a replacement windscreen in total ,some screens dependent on the type of M/H are well over £1000.00