This single piece print is a basic 3rd class Interior (no arm rests in original 3rd class compartments) for the short non-corridor Clerestory composte/third class coach first produced by Tri-ang and then Hornby in various liveries. Catalog numbers:R332 (Triang) and R4913 (Hornby Railroad).
Please check that the body part number, found on the underside of the Hornby versions of the coach. is S5821 before ordering.
I have also produced a multiple part kit for a camping coach interior for this coach available
here.
An interior for the brake coach (body Part Number S5803) is also available on this site
here.