Roger M (who certainly knows a good deal more about this subject than I do) has contacted Bill W (who wrote to us about the "vintage tinplate coach" for sale in the June Newsletter).
Roger believes that the coach is not Gauge '3' (nor Carette) but is possibly a vintage Gauge '2' or maybe even a Gauge '1' coach body. So I suspect the lack of the original bogies did confuse the issue more than a little. If you are still interested - contact the Editor as per the letter.
And for the curious amongst you - this is what it looked like!