Well finally got a chance to look at them, then realised I have confused replacing the M/C on a Series 2a lightweight (no servo, single line) with my later series 3 with dual line and servo system, which doesn't have any adjustment on the actuating rod, that I can see, does it? Have the factory manual to hand and it is not mentioned at all.
If there is no adjustment, I'll get a M/C ordered up, and no it won't be in a blue box!
Brake fluid looks slightly mucky too, so would fit with the M/C being U/S.... is it worth trying a rebuild kit? Not tried one before, just dropped new Lockheed ones in place...