The laws for cars in Spain with foreign registrations are quite clear - you can only use the car for 6 months in any one year (theoretically it should be out of the country for the rest of the time) AND it must be fully legal in its own country of registration. That means that you must have a current road tax disc displayed, have an MOT certificate if applicable and at least third party insurance. This seems to point to the insurance needing to be issued in the UK with an extended 'green card' for overseas use.
If you are leaving the car in Spain how are you going to get it through its MOT test when it is due?
Best thing is to get it onto Spanish plates as soon as you can - pay the Spanish road tax, have Spanish insurance and have a Spanish MOT (ITV) test - this way you will have no worries and everything will be fully legal.
Jon
This message was last edited by jjh on 12/03/2010.