Thanks Colin, yes hoping to be at Sudbury this weekend with engine in hand... Well, in a box, in my hand...
John, I can't really take much credit for the method of weathering, I learnt everything from EastSidePilot and Buckjumper of this parish..
A simple (?!) case of mix up your weathering colour, something along the lines of a warm grey if that makes sense. With an airbrush, spray light coats, and then whilst still damp, using cotton buds and enamel thinners try to get as much of the paint of as you can. Repeat the process a number of times until until you have the desire light/heavy weathering effect.
The 'The Art Of Weathering' book by Martyn Welch is the bible that you need to hand really...
Hope it helps..!
JB.