Thanks mate, but that seems to be exactly what I've got right now. 40mm high with a bolt right at the top.
After a bit of research, if anyone has a syntace f99 or f139 for sells (26 clamp in 100 or 110 length) then I might buy it off you. Or maybe a deda Newton 26.
Pro LT apparently has a 40mm stack heigh exactly. Mine (100mm) is yours for a tenner if you want it.