Not ever having seen this model apart, is there any prospect of positioning the decoder in the cab? I have the class 15 and 16 models from Heljan, and on both the treatment of the cab interior below the window line eats into available interior space, a thick moulding positioned well above the mechanism parts. On the class 16 this was visually intrusive, and I replaced it with a folded piece of black paper which concealed the mechanism and took up much less space and was thus 'invisible'. Had it been necessary to find space for a decoder on this model that would have made a suitable location.