Thanks for the comments wattsup and papaone. David owns a model shop and I have sometimes done a kit of previous models for sale through him. I am retired and the building is a hobby and is certainly not a commercial venture for me. I have done a couple of builds for other people and enjoy it as long as there is no time pressure to take the fun out of it. I enjoy the challenge of trying to build as light as I can. Unfortunately light balsa is hard to get at the moment so that is adding some difficulty