Mystery solved:
I wrote to Tokai, and - while they don't have detailed records by serial number - they have looked at the images and their records and they believe that it is indeed a special run, made for the UK, a ULS150-AAA.
This is an LS150 (which explains the Orange Drops Vs Black Beauty), with an AAA-flamed maple top and other appointments like the MoP headstock inlay, etc.
Other specs are as we thought - one piece mahogany back, MKII Pickups, etc.
Thanks for all of your help - a fun mystery