I think the 32 has a ribbon selector. Part of the component is up front behind the knob, then it has a sliding metal ribbon that moves the actual selector mechanism near the back. AFAICT these are no longer made, and I've only ever seen bits of one come up at auction (e.g. part of a selector for a 72
here). I doubt Naim still has any but I could be wrong.
I recall folks having varying amounts of success tearing down ribbon selectors, cleaning contacts, bending springs, etc., but I would have a backup plan in case that went badly.
If my 72 selector failed I would get a new Lorlin rotary selector (5 position 3 pole?) and then run wires back to the locations on the motherboard where the selector was mounted. You'd want to take lots of photos and notes of what pin each did before doing something like that.