The boiler is a Potterton Kingfisher, there doesn't seem to be a thermostat. I set the CH timer to come on 5.30am to 7.10 each morning - comes on fine, 12.00 to 12.15, again ok and 5.30 to 10.30 in the evening. The override switch let me turn the heating on during the day when at home but in the...