Hi there, I did fix the problem, and will remember the details I can (I have moved now so cant even look at the actuaator to remind me). Basically inthe actuator there are two microswitches, these tell the system when they are pressed so it knows where the actuators position is, in my one one of these switches was faulty. Replacing the switch was easy, it has 3 wires soldered to it, these are not small solder joints but large, easy to work with joints. The switch is also pushed down onto a pole to hold it steady, so removal is a doddle, as was replacement. I think I used trial and error to work out which switch was definatly faulty, but it was also quite possible to hear that one was not clicking as clearly as the other when pushed (and it was the quiet one that was faulty in my case). I got my replacement microswitch from RS (www.uk.rs-online.com) and it was only a few pounds, the microswitches in the actuator have all the markings on them that you need to find the replacement, and it may be worth getting 2 replacements while ordering as I think the postage for the order was more than the switch if I remember correctly and as far as I could make out the it is not that uncommon for them to fail. Anyway definatly worth a go at fixing when you consider how much a new one costs compared to a full repair cost of less than a tenner (and that would include 2 new switches). Just remember to disconnect all the power to the CH system before attemptin the repair. Hope this helps p.s. with my faulty switch I could sometimes get it temporarily working again with a squirt of wd40 and then a few pushed on the switch, but then again sometimes this didnt seem to work.