Current ATW stock is limited to the Realtrack 143, Hornby 153 and Bachmann cream/turquoise liveried 150. I am trying to get my friend who no longer railway models to sell me his ATW 158 and am debating whether to take the plunge and buy the newer ATW 150, but at £270 that money could go along way on buildings and scenics so it may have to wait. I would also like to repaint a set of Mk2s with a BR blue Mk3 buffet to go with the future release 57/3.To make some thing like the photo but probably not top and tailed. A full DVT,Mk3 and class 67 premiere service would be nice but I missed the boat when they were in the shops a couple of years ago and finding a DVT and ATW buffet now is rare with out paying through the nose.
With regards to the bay platform I have seen some photos of it, but as you said all the photos I can find only have freight workings on them. The reason for the bay on the layout is really to make running more interesting but its nice to be partially mirroring the actual station
The signal box that with sit on the 'north' side of the tracks on the layout was also taken form the box which at just off the end of the bay platforms on the south side of the tracks. This is quite a nice history about the station I found.
https://sites.google.com/site/gloucestershirerailwaymemories/home/train-services/175-years-of-trains-at-cheltenham-lansdown-station---1840-to-2015
As a stop gap I am using a modified Metcalfe station for the main building but eventually I will have a bash at scratch building it. Finally I want to represent the Midland Hotel and was wondering if there were any kits that could be kit bashed to look like it. Currently the closest I can find is the 4 Ground Railway Inn (OO-SR-110) but the windows and frontage are all wrong.