Be careful running the original water tube boiler versions of the W1 on a layout with platforms or other structure close to the track, as it is well over scale width. A slow speed test under observation wherever it is to operate would be a good plan.
For reasons known only to Hornby the cylinders are set too wide (unnecessarily, their Gresley pacifics have them correctly positioned) which in turn means the width over the valvegear is too great, and this prototype had the very awkward feature of the front footsteps to rear of the cylinders, and thus over the valve gear. This feature was never going to be possible at scale width in a RTR OO model, but having the model's cylinders and valvegear unnecessarily wide compounds the problem.
Hopefully Hornby haven't boobed in like fashion on the rebuilt W1, or the front end proportions won't be right, and while we no longer have this loco to look at, the A4 has the very same front end styling....