[rovertone]

Similarly I have done many trips down through Spain to the Algarve. Speaking from an unfortunate experience my tip would be to keep aware when stopping at motorway service areas.
About 4 years ago we stopped for a comfort break in the basque region, parked right next to the cafeteria, nipped in to the toilets, came out and found front n/s tyre flat.
Pulled a few yards across the car park for space to change wheel when an over friendly guy came over whilst we were emptying the boot insisting that his mechanic at the depot he was pointing to on the other side of the motorway could help with the tyre. I got a bit frustrated with his insistence, not requiring help to change a wheel. We soon discovered the reason for his close attention his accomplice had taken my wife's two handbags from the passenger footwell while we were distracted. Of course i subsequently discovered that my front tyre had been stanley knifed through the side wall.
The police told us that distraction crime is not uncommon on service areas. We have subsequently heard of other similar distraction methods so the moral of my story is if anyone approaches for whatever reason stop, check, be aware that their intentions may not be honourable. Having said that ,lesson learned and I can't wait to get back on spanish roads again.