I did fabricate it in the end, it actually ended up very satisfying. If you look at my build diary there are some photos in there -
www.deepfolly.co.uk
It was quite tricky to get the two hoops of 3mm x 25mm steel to form properly - because the front of the scuttle is smaller than the back the rear hoop has to kind of angle inwards and downwards so the skin goes on properly. It took a fair bit of messing about but then I have never done anything like it before so if you know what you are doing you will find it easier than I did.
Hope that helps,
Enoch