That looks a really nice place Andrew. We have a few reservoirs in Mallorca but I have never seen any kind of model boating activity. There are a couple of big ones up in the mountains that would be ideal but the main problem which is quite Spanish but very Mallorquin is that virtually all the here land is privately owned (around 97%) and the owners are extremely territorial believe you me.
Most of the boating here seems to be done in harbours and off sheltered beaches.
If there is one thing I miss about the UK it is the modelling scene of all disciplines.
Tim R