Hi Davenutt, yes it’s what the PO used to call the ‘limpet’ and it’s the fixed provision for the magnetic alarm contact. That bits fixed rigid on the door, usually over the keyhole, and the ‘limpet’ was the magnetic box powered on an armoured cable which fitted into it. Once set, Removing it to put the key in the door or to swing the door open would activate the alarm. You’ll see them on all the oldies, the standard PO issue Tanns, Stratfords and the big bankers Grade 1A’s, free standing, wall-set counter safes and the strongroom doors as well.
