Coupling brackets on carb flexible rods XK120

Can someone please advise me of the correct finish for the brass couplers either side of the spiral-wound flexible section on the firewall side of the carbs? I believe they should probably be nickel plated. Are the small bolts and nuts similarly plated as well? I’m not sure of the thread size of these small bolts, and I haven’t yet found a source for new special deep nuts for them, so I may end up having to take them to the platers.

Definitely plated with something, probably nickel as it is not as shiny as chrome would be.
The bolts and nuts, too.
The bolts are #2BA x 3/4" hex head and the nuts are thick, what are called heavy nuts here.

As Rob notes, they are 2BA. Here in the U.S. they are listed in Moss Motors’ online catalog for Austin Healey 100 and MGA carburetor parts.

But whether the dimensions of today’s 2BA replacement fasteners are the same as those from the 1950s is uncertain. Here’s the measurements of an original 2BA nut supplied by SU: .34 inch across flats by .20 inch tall. The head of the 2BA setscrew is slightly smaller at .318 across flats.

Thanks Rob and Mike - that helps! I will look into what Moss can supply which would be easier than re-plating, although I’ll be doing the clamps anyway.
Rob, I notice that your pictures show the reverse-wound link which would be correct for a pre-war Jag, I believe. On an XK engine it would tend to “unwind” in operation, thus introducing a TINY amount of lost motion. I picked up a nice correct (for an XK) one the other day to replace my less than perfect one.

Yes, I should have said it is for my 1950 Mark V pushrod engine which has the carbs on the left side. Anyway, evidence that they were plating them in 1950.

I purchased a new spring shaft and couplings from guy broad for my 140 fhc - they were brass finish, think they came from SU. I unfortunately had to go with a cable throttle in the end so mine are surplus - can send photo if you like.

Ah, that all makes sense, Rob.

Thanks, Scott. I’m OK for parts, thanks. I think I have a new coupling somewhere, and a new spring shaft. Unfortunately, SU can only supply reverse-wound ones as for pushrod Jags these days, surprisingly. Fortunately I have a couple of original XK ones.