Does anyone have any suggestions as to the easiest way to free them off without having to completely pull the whole bank apart?
The seized part is on the throttle rail, from the left: between the pulley and the first spring and there's also some impediment to free movement under the third spring, too.
Bear in mind that this photo is inverted relative to the following parts diagram:
Having looked through the CMSNL parts lists, it would appear that the carbs themselves are effectively single unit items, so it looks like this has to be freed off or the whole thing's largely toast. Having checked underneath the circlip that goes between part 1 and the pulley-bearing carb, there appears to be some kind of soft fibrous padding in there. It looks too regular to be accumulated crap, but it's in the kind of place that I'd have thought would be better served by a PTFE bush.
Does anyone have any suggestions as to how best to loosen the throttle action on these carbs up in situ, or am I looking at stripping them down completely?