@ Techdeth... Marshall never stopped making 1959 Superleads... when the JMP master volume amps came out they were just added to the lineup. They made 1959's well into the JCM800 lines.
I never knew this about the UK Marshall cab grillcoths and I even have the Big Book of Marshall. Learn something new every day........
I guess in the UK Marshall cabs were the black cane grills I found this out there in the aether....
Salt and pepper basket weave was there from 1968-1970, 1971-1975 was large checkerboard, 1976 to 1979 was small check for USA models, black face for UK and from 1980 all were black face. Give or take a year at each stage.
Also, the brown cloth seen in early 80's is faded black, there were no brown grilles used at that time apart from club and country combos which were also covered in chocolate tolex if I recall. It did fade almost instantly so you have guys who say it was brown when they bought it, but definitely faded black.
Yes, uk cabs are black from about 76/77 or so.