S2a Choke Control

My 1965 2a has at some point had a different choke control knob fitted that does not have a switch to turn on the dash warning light. That's no problem but in the interest of trying to maintain originality I've spotted that there is the correct type for sale on fleabay. My questions are;

Are these a rare item?
Will it contect up ok with my weber carb?
If the cable in knackered, is the whole unit knackered or can the cable be replaced on its own?

It's a fairly pricey Buy It Now and not sure that I should be bothering with such a thing but any answers will help with my decision.
Thanks

Not sure on the cost but or how rare they are but they will work with a webber (does on mine) because the warning light is controled by a temp sensor on the cylinder head just to the left (NS) of the radiator thermostat and a switch on the choke cable mounted where the cable go's through the bulkhead.

Thanks clivees! There is a bit more to it than I thought, I'd presumed there was just a switch that lit up a light to remind you that the choke is pulled out. I guess now that it is a light to tell you when you need to be using the choke in relation to engine temperature?

Yep the light come on when she is up to temperature.

Have a look at the circuit diagrams

Cheers! Been and checked my landy, checked the parts list, checked the wiring diagrams, checked crapdocks pricelist, checked my bank account, checked ebay and bought a second hand cable and switch. Hope it works!
Thankyou!
Thats another job to add to my rebuild list........

Possibly too late for you now, but be careful. On a Ser III the cable is stretched to the limit (or perhaps beyond, depending on tolerance in manufacture) when connected to a Webber. Some will fit some (most?) won't.
I don't know if the same is true of Ser II.

On a 2A the choke knob is fitted next to the starter button just below the dash, and therefor about 12 inches less than a series 3 is required.

Well if there is a problem, I'm sure I'll find a way around it. Won't be finding out for a few months though!