As found on service sheets 351 & 352.
Hornby X6203 Class 2800 / 3800 Coupling Rods & Valve Gear
Hornby X6203 Class 2800 3800 Coupling Rods & Valve Gear R2915 R2916 R2917 R2918
Hornby (GB) Class 2800 loco 2-8-0 rolling chassis with glowing firebox - vgc