Still finding more stuff, and I haven't got to the basses or rig yet...
3 x wooden thumbrests made by Guy Lewis. 1 x ebony (?), 2 x maple (?)
I briefly used a 'maple' for a while, but can't tell which - they're basically as new.
My guess is the lighter coloured aren't maple, but the darker may well be ebony.
The screws I have which I THINK are the ones supplied protrude 3/4" when seated. If in doubt, try some shorter ones first! Black screws for the 'ebony' and chrome for the 'maple'.
I'll take £9 for each, with £4 to cover postage for any one or more.