Zio Nick, indeed, but the OP is specifically looking for a D model.
Flying Pinguin, it doesn't matter where you look, there are only 6 D models in existence, 5 at Dundee, and one other in Europe. They made 7, but one is beyond repair.
Admittedly the E model isn't too different, so perhaps that's where you should be looking. The A model is vastly different, and will cost an awful lot more, but will be easily sourced as there are plenty about.
Last edited by RTN11; 17th Jan 2013 at 14:48.