John
Cooling issues in the south of europe are normal, I guess that your RV just like my DR400 gets its speed from being very efficient aerodynamically, some of this is due to not having too much cooling drag.
The result of this is that the cooling is enough for the cruise but at climb speed and Power there is not enough cooling, this is managed by step climbing the aircraft, the DR400 at MTOW with a ground OAT of +30C can expect to climb to 4000ft before the oil temperature climbs to the upper end of the Green part of the gauge and 5000 ft will probably just short of the red line.
Simply stopping the climb and setting up the 60% power cruise will bring the oil temp back to the normal range within a few min.
In the UK where we are usualy hard pressed to get above 5000 ft due to Class A airspace and dont have too much high ground to deal with oil temp is not a perfomance issue but at places like Granada that can hit +40C in the summer and is surounded by high ground oli temp issues can govern your ability in climb clear of terrain.
An early start is sometimes required in central Spain before the heat of the day kills the climb performance. Also you should choose the altitude you wish to stop the (step) climb at, most long range flying is done VFR on airways and being forced to stop at the IFR level going in the wrong direction wont make you any friends with ATC so plan your climb so that you can get to the next VFR level before the oil temp gets out of limits ( if you dont quite get to the next VFR level at least you will be at the IFR level going the right way!).