First to the original poster. If you notified the Dvla before coming to Spain that the vehicle was being exported then ,basically having not been re.registered , it does not exist. When you notify the dvla of permanent export the vehicle registration is WITHDRAWN & does not show up in any database. It is possible that if it was a ' catchy ' plate they coud have flogged it on to someone else, whilst you still think it is yours.
Uk regulations require the vehicle to be legal in the UK. EU rules, which take precedence, require the vehicle to be legal & registered in its own country to be legal anywhere it is being driven !
If the vehicle has been SORN'd it cannot be anywhere else but in th UK. It is Statutory Off Road Notice , in the UK. It can't be sorn'd outside of the UK nor can it be sorn'd , in the UK, then taken out. In either respect it would be a fraudulent application.