So I've been through the 173 pdf's on Grabcad and unless I'm blind I couldn't find a drawing for the clam to chassis bracket.
I've seen the Taylors drawing before BUT in my simple mind that wouldn't hold the clam securely to the chassis, as mentioned the SGT has a bolt that locks the bracket to the bobbin but makes the bracket maybe 20mm thick, thicker than I'd like..... same with the ebay ones Morten linked... there's nothing locking the bracket to the bobbins