What a travel Back to the jungle, anyway cut & pasted this from one of the bloggs on main site if it helps. There is a lot of advice good & bad as you well know on the site, the focus would have been ok for us if Sean had not stolen it before we looked at it.
I can't understand why you want to buy a cheap UK car to leave here when you can buy a cheap Spanish one that will give you less grief driving it around with the police etc. (also toll booths are a nightmare when you are on your own in a RHD car) just one example.
If you bought over a UK car you would have to take it back every year for the MOT, a Spanish ITV (MOT) won't be legal. Without the MOT you can't get your road tax and without both of these I would guess that any insurance you had would be void.
After saying that its also against the law to keep a UK car here for more than 3 months without changing the registration although many have in the past the traffico are now starting to clamp down.
I couldn't do with the constant worry.
Have a look a this beauty, using your example ie 4k ford focus estate
Lot of car for the money 06, high miles but as you said parts are cheap