'Part Number: X1707. Also known as X1123. The Sliders and Rods are included as pictured. This valve gear is shown on Hornby service sheet 131. Whether you can use it for the earlier model I don't know - sorry.
Hornby X1707 Class A1 / A3 Valve Gear Left Hand
Hornby X1707 / X1708 Older A1 / A3 / A4 Valve Gear
