"Murmansk" wrote in message
...
These are what I fitted - they seem pretty good

http://www.ebay.co.uk/itm/ENFIELD-GA...e m337eb7005d

I don't think the standard lock is very secure - mine has a piece of wire
that links to a bolt at the top - if you were to drill a tiny hole in the
centre of the door you could push the wire and make it withdraw the top
bolt.

Same here, it's a kind of push-lever in the middle of the door, when you
push the lever it pulls a wire which splits into a "V" and pulls down on a
latch each side, pulling them out of holes on the top of the doorframe.