The first panel I ever installed was a metal cased Logic 4 that I bought for 50p off a car boot when I was 9 years old (I still think I got ripped off!). I put it in our shed and had it wired to a carbon Ever Ready 12v battery that I got from B&Q. I had a microswitch on the door and another on the roof incase anyone tried to lift it off. Master Bell outside...
I've serviced quite alot of old Logic 4, Genco and Bentley panels, all of which were still going strong long after the original contacts, pressure matts and Friedland bells had been changed out due to failure.
I've ripped a panel out that sounds like the one Alarm Guard is describing. 1 zone, Keyswitch on the top left or top right, blue hammerite casing with a black plastic control panel with white lettering on, and three LEDs in the middle. Had been fitted by AID alarms of Liverpool, I believe. Wish I'd have kept it now...