Other places you could try are SE finecast as tehy produce a whitemetal A4 and Wessex Proscale as they have a brass A4 with a w/m chimney. Proscale are availaible through intercity models I think. They may be able to help you. The man who probably knows best about stuff like that is Dave Cleal at Mainly Trains. He has loads of bits and bobs availaible.