Bottom line up front: This fix doesn't work for the 1200/1250LC - the functionality is the same but the microswitches are not only conjoined, but also partially encapsulated in a plastic casing that includes a three pin socket rather than trailing lead.
Nevertheless, I succeeded in effecting a fix, although as I didn't have the opportunity to delve inside the offending microswitch, I don't know its condition and it may well continue its failure mode some time in the future.
The configuration is similar to the 1600 - two stacked switches with the starter safety switch uppermost. The tab of the cruise control switch is depressed in the neutral position and releases when the clutch lever is depressed even slightly, facilitating immediate disengagement of the cruise control before any clutch slippage could possibly occur with the engine still under load. The starter safety switch engages much later, ensuring the clutch is fully released before the starter motor engages.
My starter safety switch was not triggering at all, even with the clutch lever fully depressed. With the micro-switch assembly removed and the switch tab depressed by hand, it would operate correctly. I had the GS911 hooked up so that I could monitor operation via real-time values, 'Clutch switch' being the starter safety and 'Clutch switch 2' being cruise control disengagement microswitch.
The safety switch tab showed signs of wear, so I super-glued a shim plate (cut from a safety razor blade with scissors) on the under side, overlapping a glob of 5 minute epoxy glue on the trailing end to ensure it remained in place should the superglue gave way with use and flexing of the tab. One needs to be accurate in placing the shim as the superglue locks it in place once any pressure is applied. The shim made the switch trigger earlier, but not enough, so I added two more on the upper side, this time without removing the tab from the switch.
I noted in my testing that the switch only triggers some distance past the 'click' so I don't know if this fix will be enduring.
After assembling and testing to confirm satisfactory operation, I removed the switch to place some dry lube on the tabs and lever triggers.
The separate clicks of the microswitches are now clearly audible at the beginning and towards the end of clutch lever travel when pulling the lever in. The starter safety switch now triggers when the lever is about a centimetre from the grip. I'd be interested to know whether this is a typical distance.