Dingle, I checked my own records. CVR coaches were all the same, as were C & L ones, in terms of overall dimensions and other details. Those of each line were ordered at the same time, from the same firm (Metropolitan Railway Carriage and Wagon Co., Birmingham), and were even delivered painted the same colour - a reddish-brown, which apart dfrom obvious differences in lettering etc., therefore bore the same livery. Another uncanny similarity is that a proposal was made by the directors of each company in the early years of the 20th Century to acquire further coaching stock to cope with heavy traffic, but in each case other directors voted the proposal down on grounds of finance!
C & L coaches were 40ft long and had 14 windows, while CVR ones had indeed two lengths. First class coaches were 24ft long, and thirds were 29ft 6ins. In all cases, the length refers to the chassis, the body obviously being shorter in all cases by the width of the balconies, i.e. bodies themselves were 5ft 6ins shorter.
The circular seats you see were not loose chairs, but fixed swivel chairs, but they proved unsatisfactory on at least the C & L line and were later replaced with fixed seats. They were covered in black leather.
The CVR used a crest in the earlier days, but possibly not right at the outset. This was certainly in use after 1903, but later a gold leaf "CVR" monogram was used, and later still the initials "C V R". The C & L didn not have a crest, but used well spaced out lettering, but after 1925 this was replaced by GSR maroon, unlines, but with full crest and standard pattern shaded numerals, as on other C & L stock, broad and narrow gauge. The GSR painted the carriage roofs light grey. I believe the CVR used a mid grey. On both lines the carriage chassis were black as one would expect.
Hope this helps.