The givi lock barrel in the trekker alloy box, can be modified,
This involves stripping the barrel down and making the slot bigger to take the bmw key,
If you fancy having a go this is how to do it,
Carefully take the stainless trim off, and the revealed plastic shutters and springs,
Push all the wafers out including springs, and window plate,
Using a small square file extend the slot so the key slides in fully without excess play,
Then file the window box plate to allow the key to pass through, then re fit,
Re fit the shutters and springs and trim over the opening,
Then fit wafers trial and error so they are flush with the key entered,
Starting at the key opening end, getting one in past the shear point at least,
You wont get them all in as the bmw key is shorter, make sure they are flush then try in the sleeve to check function, slight filing of the outer edges of wafers may be needed,
If its all smooth, build it back up, there are oppinions on lubing so thats your choice
Not aware of a bmw barrel that fits the givi case,
It takes me app 30 / 40 minutes to strip modify and re build the barrel,
Roamer