As found on service sheet 374 for various B1 locos, however being black I think they are only designed for R2998.
Hornby Genuine X6495 Black Buffers For R2998 Class B1 Thompson Roedeer Tender
Hornby Genuine Spares X9075W Cylinder Valve Block For Black 5 Loco For R2258 5MT
Hornby Genuine Spares X9412M Coupling Pack Class 60 CL60 Pack of 2 NEM Couplers
Hornby Genuine Spares X9289 Pack of 2 NEM Couplers Couplings NEW
