Probably...

Also, the Police are getting a bit shirty about foreign registered cars, one friend has had his towed by Policia Local and not returned as "It has been in Catalunya for over a month, so must be re registered"

Yes folks, never mind European Law, if asked, tell them you come and go all the time, this person had receipts for a trip home and its MOTing [equivalent] from just a couple of months ago.