Correction- Its Alembic Essence 6-string No. 94 K 8399 !
Dear Slawie, thank you for an inspired piece of detective work - on closer inspection in good light, the last four digits were 8399 not 6399. The number stamp left the right-hand side of the top part of the 8 open, so that it looked like a 6. Mystery is solved, thanks. The identification link you gave me would be therefore correct:-
Alembic Essence 6-string No. 94 K 8399 -
top: Bubinga
accent: Maple pinstripe
body: Mahogany
neck: Maple with Walnut pinstripes, 34 long scale
fingerboard: Ebony, no inlays
pickups: MXY56
controls: volume, pan, filter, mono output
birthday: June 17, 1994
originally made for: Guitar Center
The bass used to be played by an American friend of mine in Ireland (a very fine bass and guitar player) whose life was tragically cut short by a car crash in foggy weather on the way home from a gig.