After a few close to accidents I started looking for what´s on the Internet regarding driving in roundabouts. I found the following explaining why Spanish drivers behaved as they did.
Credit to johncar61
........or driving into the side of you as the spanish dont know how to use roundabouts.
The law in Spain about driving on a roundabout is different from probably what most most people think.
It is not the same as UK.
A person turning left at a crossroad with a roundabout can legally use the nearside lane (right hand lane) on the approach and all the way round the roundabout.
A person doing the same but using the off-side (left hand lane) to go around the roundabout has no right to signal right as they approach the turn off road and then cross into the nearside lane (right hand one) to turn off the roundabout.
If there is a car using the inside lane (nearside lane)they must go around the roundabout again, until they are allowed to move into the lane they want or until there is no other traffic in that lane.
I hope this makes sense (not that it is sensible). If not please check out the Spanish Guía de circulación (highway code).
Gordon