As supplied, the lock tongue on my replacement locks would not slide back on making contact with the door striker knob. The tongue was far too long in its reach and the contact angle was too sharp. It simply slammed against the striker knob and the lock would not operate. The manufacturer clearly never tried the lock as a complete system on a door striker.

In the graphic, on the left is shown the lock tongue length and strike angle as originally supplied, and the modified one on the right. In the modified form, the lock tongue is reduced in length by 2mm and the angle of the tongue has been reground to create a more parallel strike angle to that of the door striker knob. There is still ample projection of the tongue in both the first and second holes of the door striker. It works beautifully now. The supplier has been informed.

Notes: The relevant part numbers are, AFH1682 (R/H door lock) and AFH1683 (L/H door lock). This modification is applicable to the door locks on all MGA roadsters.