If I may?
Sleeper coaches: (FGW dynamic lines unless stated as GWR silver & green)
RFM:
10217 (ex-Virgin, undergoing refurb at Wolverton as a replacement for 10232),
10219,
10225,
10232 (not getting refurbished as severe corrosion means going off-lease, and probably scrap),
SLEP:
10532,
10534,
10563,
10584,
10589,
10590,
10594,
10596,
10601,
10612,
10616,
TSO:
12100,
12142,
12161,
BFO:
17173,
17174,
17175
THe GWR Livery thread and @co-tr-paul's thrad on Night Riviera updates should provide a useful reference point for you.