Carb problems

A new problem has cropped up. Part of the carburettor linkage keeps on coming off. There's a ball-and-socket joint that keeps on popping out. I don't think the offending part can be replaced on it's own (it ain't listed in the parts catalogue or on Rimmer Bros' website) so I can either cannibalise one of my spare carbs or fit Toledo's carb. (it is exactly the same - an SU HS4) Until I can sort it out I think I'll have to put Becky back into daily use. I can't keep on refitting the linkage every time it pops out.