In an effort to move this forward a notch:
Brabham drivers in UK 1963 (from formula2.net)
Rodney Banting - BT6
[FJ-4-63]
John Dunn (Green Man Garage) - BT6
[FJ-7-63]
Frank Gardner (Ian Walker (Racing)) - BT6
[FJ-6-63]
Mike Hailwood (Reg Parnell Racing) - BT6
[FJ-10-63?]
Paul Hawkins (Reg Parnell Racing) - BT6
[FJ-3-63?]
Denny Hulme (works) - BT6
[FJ-9-63?]
Roy James - BT6
[FJ-1-63?]
Bob Olthoff - BT2
[FJ-6-62]
Denis O'Sullivan (Motor Racing Stables) - BT6
[FJ-12-63]
David Prophet - BT6
[FJ-5-63]
Cliff Ward - BT2
[FJ-9-62] and 'BT6' (the BT2 again?)
Also elsewhere in Europe (from formula2.net)
Giorgio Acutis (Scuderia Centro Sud, I) - BT6
is this [FJ-11-63]?
Curt Lincoln (Scuderia Askolin, SF) - BT6
[FJ-8-63]
Philippe Martel (F) - BT2
[unknown] and BT6
[FJ-2-63]
John Peterson (North Star Racing Team) - BT6
[FJ-13-63]
Jo Schlesser (Ecurie Ford France, F) - BT6
[FJ-14-63]
Klaas ’Jimmy’ Twisk (The Tulip Stable, NL) - BT2
[FJ-4-62]
BT6s that aren't seen in Europe
(FJ-1-63 and FJ-2-63 aren't easy to decipher)
FJ-15-63 in Australia
FJ-16-63 "Betty Haig, Peter Richardson" - who?
FJ-17-63 in Switzerland
FJ-18-63 in New Zealand
FJ-19-63 Bruce Kessler (US) in SCCA FJ racing 1964
FJ-20-63 Graham White (Langley Garage, Cheam) in 1965. No sign of either in 1964.
Can anyone help with some of the question marks? The Chequered Flag
libre car isn't easy to spot in this but FJ-16-63 and FJ-20-63 are possibilities.
Allen