You may, or may not, know that the standard lock on the exterior hatch is keyed with the ubiquitous "CH751" lock, for which everyone and their cousins have a key. Rather than replacing the lock with another keyed version, I changed it out for a
combination cam lock.
It was necessary to rotate the finger pull by 180 degrees, and flatten it out a bit, but otherwise everything fitted together easily.
I don't know if this mod will work on newer TAB400s with the smaller door.
Roger and Sue Hill | 2020 T@B400 Boondock (Cryst@bel) | 2022 Land Rover Defender 110 - P400 | San Juan Island, WA