After placing the Top Box into the correct position on the Sliding Carriage -
pushed forwards against the stops, it locks into place when the carry handle
is pushed fully down, until it lies flush with the surrounding panel.
You won't be able to push the Handle fully down unless the lock is in place,
and it is turned to the vertical / "Removal" position against its spring return.
To fit the new Lock into your Top box, it must be orientated the correct way up.
Insert the Key into it, and hold it so the key blade is Horizontal.
Fold the handle down until it clicks into place at the Unlocked position.
The key hole / slot is offset from the centre line of the lock,
so start off by holding it so that the Key slot is Horizontal,
with the slot below the horizontal centre line, as shown in this first Photo,
with the slot lined up with the Locked padlock symbol :

Turn the Lock a quarter turn Anti Clockwise,
so the Key Slot now lines up with the Open Padlock symbol :

Start to insert the Lock into the Top Box -
You will need to depress the "7th Locking Wafer" that protrudes
from the end of the lock, using a small screwdriver or similar tool,
so that the lock can be inserted.

Push the lock all the way in to the Housing and it will Click into place.
The click is the Locking Wafer engaging in a slot at the base of the Lock cylinder.

You should now be able to turn the Key further Anti Clockwise against it's spring return,
so the key is vertical and lines up with the "Carrying / Release" symbol.
Holding the Key vertical against the spring, lined up with that symbol, push the Handle in
so that it is flush with the Top Box Panel - it should click into place with a positive feel.
While holding the handle down, allow the Key to return from it's spring pressure.
Release the Handle then turn the Key 1/4 turn Clockwise to the Locked position,
and physically check the Top Box is securely locked to the carriage before riding.
Cheers

