Would this give you a tighter bend radius?http://www.screwfix.com/prods/18625/...92-5-87-5-Acce...

I looked at that to solve a similar problem myself, and no, they're
all the same size.

Even the floplast adjustable bend introduces a similar sized offset
(it's also double socketed).

Only making the 90 degrees (or about that) up with a couple of obtuse
bends worked.