Hi Hugh, welcome to the fold and congratulations on finding a second hand body.
I've taken a look through my photo records and found some pictures of my Sammio supplied frame. I'm not sure if anyone still has the tech drawings for these or could make you one, I know Phil J fabricated at least one of the frames on the cars he's built as Sammio didn't offer them at first. I do like the idea of an exposed tube frame though.
Anyway, here's the photos and good luck with your build, it'll be nice to have another decent thread to follow!