Hi Mainline, great racing isn't it? Highly developed Brit two and four strokes, with two riders capable of overcoming the inadequacies of both! I think Bickers left Greeves for CZ in early 66, so I guess this has got to be Winter 65 season at the latest - Smith won the world 500 in 64 and 65. My best guess is early winter months of '65. This is TV not cine footage, so the video speed we are seeing on Youtube is accurate..and looks pretty quick to my eye! Bicker's riding can best be described as...mmm...'forceful'
Your uncle's bike looks great and is a tad more complete than mine at the moment, but the model is pretty much identical. By the look of it, he has his set up as 1966 MX3 with the (first year they were available) factory-optional Cerianis (it could equally have originally been an MX2 tho). Mine's an MX3, but using the 'Banana' leading link forks, as per the Bickers bike above.
Keep us up to date as your bike progresses!
Clutchslip