Swapping the gearbox out on the 65 and did this mod whilst it was on the bench. Drilled and tapped the left hand end of the rod the clutch lever clamps to and installed a 1/4" BSF bolt with stud lock. This does away with the slot Austins put in and allows you to tension the clutch mechanism with a socket whilst nipping up the clutch lever. Not my idea, but I cannot recall where I came across it, so worth posting I think.
Thanks Gordon, I knew I'd read it somewhere!
Incidentally, if you buy new clutch toggles from our favourite suppliers, I have found the holes a tad small and so need easing. Normal drilling and filing won't touch them, but a diamond round file, such as is sold to fettle your Waterford crystal when you've chipped it, does the job in seconds.