British Standard, Sashlocks And Deadlocks
All British Standard locks must conform to BS3621, this is normally stamped onto the forend of the lock along with the Kitemark symbol. Some insurance companies are now specifying that the locks must be above a certain standard (above BS3621:1980). The latest standard is BS3621:2007 and all locks supplied by Andy Stott Locksmiths conform to this newest standard.
You can tell if you have a Sashlock quite easily as it will have handles or knobs as below
Deadlocks will only have a keyhole and no handle.