That "same bright and airy feel" I would describe as "cold and spartan".
Modern Railways was talking about the interiors on the Class 800 sets - specified by the Department for Transport.
GWR will be able to specify the interiors on the AT300s itself, having ordered them itself via Eversholt Leasing, thus freed from DfT's expertise in such matters...
Are these new 9 cars all for the Oxford route??!! Hope we get some additional decent length trains down to the south west and a few less 5 cars? Guess its up to the planners, but for my mind 2 x 5 car sets or single 5 car sets off peak makes a lot more sense on Pad - Ox, and put more 9 car sets on Padd- Penz due to the increasing staffing / restaurant etc on these services....
Various reports in the rail press have indicated that they are intended for Oxford/Cotswold use, which was the case with two or three of the sets in the initial AT300 order anyway. And perhaps a Newbury peak job or two. The all-387 Thames Valley emu fleet is smaller than the previous proposed 387/365 mix anyway and with the delay to Oxford wiring, more bi-mode capacity is not going to hurt, however it is used.
Most of the Oxford peak services come from the Cotswold Line in the morning and continue that way in the evening and they are busy arriving at and leaving Oxford, so long trains are needed.
The positions of a number of starting signals at station platform ends on the Cotswold Line mean that it will not be possible to use 2x5 formations by stopping part of each set on platforms - at least until such time in the future as new signals appear - so that means nine-car sets are a necessity. There are also a few lumpy bits in the Cotswolds and Malverns where having full power all the time will not hurt.
We've been over the question of West Country portion working rather a lot already not that long ago. Do you not think GWR might just be planning to diagram nine-car sets on Pullman duties anyway?