Cut out all the glazing except for the Cab side windows, a slow process especially the way I do it. Cut out one, leave it and when I come back cut out another one.
When I fixed the white metal sides to the Hornby bogies I found the space between them was 26.7 mm. The fuel tank supplied was 25.7 mm so something had to go. As I did not want to touch the Hornby bogies I decided to take off about 2.5 mm of the white metal fuel tank.
To ensure good traction I kept all the weights from the Hornby Chassis and had a hole drilled in the steel to give access to the bogie pivot and wires.