Left-hand Drive vehicles in Continental Europe hold their value much more than they do in the UK domestic market, particularly in Spain. What is available on the second hand Spanish market, from a small hatchback to a premium-brand saloon, is often in a less than desirable condition (worlds apart from what you would describe as fair wear and tear in the UK) and with at best a patchy service history.
An increasingly popular solution is to bring your UK-registered vehicle with you to Spain. This brings you all the comfort of knowing the vehicle, its history and the familiarity of driving the car you know in an unfamiliar environment.