Bear in mind that you may well be faced with the costs of homologation, etc. for that LHD car if it is not on Spanish plates which may tot up to over 1500€ and again, what do you do if it goes wrong just after you get it to Spain. Not necessarily very likely but someone recently moved to the village bought a vehicle from a dealer near Málaga and, shortly after, the engine died, requiring several thousand Euro's worth of repairs. Málaga is 170km away from here by car and there is no public transport between here and there without several changes and taking 6-7 hours. No courtesy car was available. OK the dealer refunded the purchase price but there was still a lot of hassle to get it all sorted out and not easy when it is so far away - even worse from Spain to UK!!
We bought our vehicles locally and we get good service because we have built up a good relationship with the dealer (Main Citroen agent in the area) so whenever our car is in for anything, we have a courtesy car.