I started, some tears ago, to improve this model, albeit to BR green, the Airfix tender is a vast improvement on the Hornby effort which is a work of fiction, I think it was the same as the compound. But to me the locomotive's worst feature is the chimney Hornby's interpretation is nothing like the real thing, given what you have achieved with your model, which really looks great, I would substitute that chimney.
Rgds......Mike