This is my last attempt at playing Which. Here is the vibration alarm I mentioned in the original break-in thread. http://www.ebay.co.uk/itm/261350642631?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 All of a tenner. Does what it says on the tin. I've got it lying flat on a table, tap the table and off it goes ( for 20 seconds it says ). It's louder than the door alarm. They claim a battery life of one year, amazing on 4 LR44 hearing aid cells. This would be excellent for our big vulnerable plastic windows and roof lights, but a door if opened slowly probably would not trigger it. Downside: Obviously you have to turn them on individually. They are cheap 'n' cheerful so how long they last in a bouncing MH is unknown. So if you don't want to spend hundreds on a "proper job" but are still worried then one of these on each big window - they can be seen outside so a good deterrent plus 3 door ones and you are a lot safer.