Robert
Tony Byford is one of the main names associated with rebuilding early BMW and Bristol engines with customers all over England, Europe and USA for Road and Track use.
He has the correct colour code and paint source for Bristol 100D, 100D2 & BS Blocks.
His email address is:- Tony at abyford dot wanadoo dot co dot uk
Send him a email and he should confirm manufacturer, code and specification. (If it's not 100% correct colour itsa as near as you a likely to get.)
Keith