Our electricity bills appear to be the same, ie 75 Euro's for 2 weeks holiday use or 40 Euro's for 1 week, which does seem to be higher than we originally anticipated (we had 1 week in September and another December so they fell into the different monthly bills).
This is, of course, assuming that none of Key mare snagging staff have used any electricity whilst they've had access in our absence. We'll probably get a truer picture when we have the key back and changed the lock code on the front door so we have control over who is accessing the apartment.
However, on a lighter note, the water appears to be pretty consistent at 10 euro's every 2 months.
I must say I'm impressed with the Bank in Spain - I can view my bills online by clicking on the relevant direct debit which has been taken (only found this out the other day while browsing their website).