It is my understanding that the R in 276/014R stood voor a "revised" design.

If you look in the BSA parts books you will see:
M20
1937
76/112
1938
76/014
1939
76/014 for the home market (M20 standard and De Luxe)
276/014R for export (M20 Standard and De Luxe)
1940
76/014 home
276/014R export

This is in the AMAL books:
AMAL settings list 1939
WD M20
276/014R
M20
76/014

AMAL Settings list 1940-1954
WD M20
276L/1E 1940-1945
276C/1B 1940-1945


Regards,
Leon

email (option): leonhop3@planet.nl

Mine is a 1940 machine, frame number WM25480 .

I'll post some photo's of the bike once I've sorted a few little 'post purchase' niggles.

Stuart

email (option): stu.gibbins@btinternet.com

PM sent. Ron

email (option): ronpier@talk21.com