Hi
We were in the same predicament last year and found out the following,
Car transport to Spain AVL logistics. These people picked up our car from our door on Monday and delivered it to CDA on Saturday evening for about £700.This was about 50% cheaper than driving it over.( our little fiesta was surrounded by 2 Porsches and a Ferrari)
We used our CDA address to register the car to get insurance through linea directa with a green card so I could drive it in the UK to have all the necessary work done to the car. Ie: cambelt/ brakes etc. Cost @ €300 for 12 months with any driver over 25
I am still in the process of re-registering the car as I have made 2 attempts to do this and every time I am asked for more documentation, the latest being the deeds to our property aswell as a signed bill of sale, logbook and any receipts for the car.
You have to register on the pardon which is done at Alhama this is the last thing we have to do then I believe there is a company on camposol that can then takeover to complete the changeover
Hope this helps
Cheers
Pat