This single piece print is a basic 3rd class Interior for the short non-corridor Clerestory brake third class coach first produced by Tri-ang and then Hornby in various liveries. Catalog numbers:R333 (Triang) and R4914 (Hornby Railroad).
Please check that the body part number, found on the underside of the Hornby versions of the coach. is S5803 before ordering.
I have also produced a multiple part kit for a camping coach interior for the R4913 composie/3rd class coach available
here.
An interior for the composite/3rd class coach (body Part Number S5821) is also available on this site
here.