I received my design for the Opus Anglicanum laid and couched piece! It is on a fabric 16" square, although the design isn't quite that large -- about 10 high by 11.25 wide. Alas, it hasn't been drawn quite in the centre of the fabric, so I'm having a certain amount of trouble finding a frame I can put it onto for stitching. It needs to be held very tightly -- laced, in fact. I was going to stitch it to a roller frame and then lace the sides, which I think will work
if only I can find the correct size roller frame... it's around somewhere. The side bars aren't long enough, though, to keep the whole design in view, which I suspect will be an issue. Can't find stretcher bars the right size, either.

Did find a cheap-ish slate frame (Siesta frames... not quite Jenny Adin-Christie!) and have asked them what the inside dimensions are on one particular configuration. (Lesson to self: don't leave it so late!!)