Superb, Glover, absolutely superb.
There were quite a few six wheeled passenger brakes about - two as late as 1968 anyway. One of these was the 1964 one. The other was 69, now heavily rebuilt at Downpatrick. 69 was built in 1888. Your one was built probably 1895-1900.
There were only these two six wheelers, possibly one or two more at absolute most, which attained the Black and Tan livery. Others remained green until withdrawn between 1960 and 1965.
No passenger carrying six wheeler was ever black'n'tan. All remaining ones were in Cork as spare vehicles by 1963, and there appears to have been a single occasion in spring 1964 when a set of them not to Youghal and back. That was that, a far as six wheelers were concerned.
The one you have modelled so well is of GSWR origin. It lasted at least until 1965 which is the last pic I've seen of it. However, the vast majority of surviving six wheelers were ex-MGWR, and thus, with no kit available for either the passenger or brake versions, this represents a major omission in the kit world - as does a standard Irish 30ft coach chassis.