So, the M/C I acquired above was a no show. Apparently it was "damaged in storage" and the buyer wouldn't sell it to me. Gave me a full refund so I can't complain about the service but, for a while, I was back on the hunt. Took Machine's advice from post #2, searched the wrecker's listings and found this one off a '95 Virago in Sydney for $95 (AUD) delivered. One of the cap screws was buggered but I organised new ones and a new reservoir diaphragm, cleaned it up and now it looks like this, (see photos). The piston action appears smooth so I haven't fitted a new kit. Will paint it up, (I actually like it as shown but I've bought a new black lever in anticipation of giving it a coat of paint and the clutch side is black), put it on the bike and see if it works without leaks.
In terms of the cylinder kit, the ridiculously cheap item from Banggood in Gary's post #23, is 12.7mm. Can you tell me if it will fit this 1/2" XV master which should nominally be 12.5mm? If this master leaks or doesn't pump brake fluid, I'd like to buy a few of these and fit one.