Thanks Steve, I can feel the fog clearing!!! I have a roundhead Student Mk1 6" straight bed, with english and metric screwcutting. The fact that the Dominion comes in 12" and 13" will be down to very early models being 6" centre height, and later, mine included (I think) being 6.5" CH. Thanks for your post, I have "advanced a tech level"
Phil.