Ok following on from my post with my renters asking for 2 sets of keys, they only got one with the electric saver on it, so they unsoldered it, left the card in the slot and went out. got an electric bill for £160ish for their stay (2 weeks), not impressed, so next year everyone has to suffer, paying for their electric via the previously mentioned meter the most annoying part is its only friends and family that use it.