British made Gillettes weren't date stamped in the same way the US ones were.
For a US Gillette you are looking for a date code of R, and if you are lucky Q, but they soon stopped using Q when they realised it looked like O and switched to using R for the year, then the number between 1 and 4 dictates the quarter of the year it was manufactured.
Randomly I have just bought a 1971 Super Adjustable from the bay, not because I wanted the year, but I wanted a Super Adjustable.
If I find a decent '74 version then I'll sell on the '71 version.
I believe your choices are
3 piece tech
Black Handle Super Speed
Black Handle Super Adjustable
The Knack
Thanks for the speedy reply ill hound the Bay untill I find one.