Just to wrap this up, the parts arrived from modell-land.de yesterday:
The green doors are not a perfect match but far far better than any of my attempts to mix the same green.
Loco complete:
I added a grab rail to the front with some plastic rod, and modified the "snow plough" - see picture in post #1.
I painted some "brass" trim on the steam dome and whistle, and painted the rear of the loco "below the water line" red along with the cab grab rails. With the number plates added it looks as good as new, ready to join my modest U class fleet.