When I looked at the list of parts on the SA web site I could not see the individual cast part listed that I refer to so I sent them the same photo of the parts as I posted here and they replied saying I needed to order the whole assembly, as you suggest Roy. The brass pin is listed separately however. So to get the part required it seems you must order the whole asembly @ £106. That being said it was not available at the time.
(For general information)
No, and it is unlikely ever to be stocked. Since it is so expensive and the main part is hand made, they will only make them to order. So if you want one from their website you must place an order. As it was not obvious from their website I have clarified this with Felix, and he has confirmed that anything not in stock can still be had but you must place an order.
Roy