
This reminds me of an incident 2 summers ago when we drove back to the UK in our Spanish registered right hand drive Landcruiser. We were stopped by some police in London doing tax disc spot checks. The policeman (only just as he looked about 15) asked why we were not displaying a valid tax disc. We pointed out to him that although it was a right hand drive it was infact a foreign plated car. He then looked and acknowledged this and asked to see the documents - which we handed over. He "inspected" the green Tajeta Inspeccion de Vehiculos nodded and said everything was inorder - he looked at it upside down - which shows that the Spanish police are onto something by sending its officers on a course!
Other regulations are the same as in the UK: Do not use your mobile whilst driving unless its a hands free system, driver and passengers must all wear seatbelts and alcohol limits to be under 0.25mg/l in exhaled air ie. when breathalised. The sensible option is to not drink at all if you intend to drive.
The Guardia Civil are especially on the look out at this busy time of the year so take extra care.