Hers a few to be going on with...
http://www.milanuncios.com/autocaravanas-de-segunda-mano-en-malaga/
One small point to bear in mind concerns your licence... on a car licence you can drive up to 7500Kgms if that licence was issued before Jan 1st 1997; if it was issued after that date you are limited to 3500Kgms.
This 3500 Kg limitation automatically rules out most if not all of the big Yank Tank motorhomes and in any event there is little or no mechanical or tech support for these vehicles in Spain. (I know this from bitter experience!)
Be aware also that roadside assistance insurance cover in the event of a breakdown can be difficult to obtain and is limited by the age and size of the vehicle in question.
As for purchasing here or in the UK, if you buy a UK reg you will be subject to all of the problems associated with driving / owning a UK reg vehicle in Spain, requiring valid uk road tax and a uk MOT at all times. A Spanish reg vehicle is by far the easier option even if it costs a little more initially...
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