one has a MH bezel, am I right in thinking that the MH bezel is incorrect or was a choice of bezels avalible??

I beleive that the Viceroy came only with the Tachy bezel. still, we see a lot of Viceroys (maybe one in five) that have the MH bezel, and there is even one of these in the TAG-Heuer archives (shown on the page below, at the right). My guess is that some owners preferred the MH bezel, and had them switched (not as a choice when they purchased them, but through after-market service).

what about a crystal for a Viceroy and a second hand for a Siffert,or at least can someone tell me what colour paint I can use to touch the hand in

the crystals for any of these seem to be in good supply. I'm not sure what to recommend in terms of the paint color.

anybody have any ideas of where to source these?

If you were in the U.S., I would recommend TAG-Heuer service, in Springfield, New Jersey. I'm not sure what to suggest for the U.K., but maybe some other readers will have a recommendation.