ok chaps, this is the reply from the guy I found:
"Hi Bill,
you'd better sit down!
the grade i've had reccomended by the stainless steel advisory service (bssa) is either cold drawn 316 or duplex 2205, both have a tensile strength of around 800mpa. I'd go for the 2205 as its got better corrosion resistance with the same strength, and not much difference in price. you can't get either in hex bar so the hex will have to be milled on.
110mm bolts 22 a/f 10 off = £18 each, 100 off = £15 each
82mm bolts 10 off = £17 each, 100 off = £14 each
the closest bar available is 25mm, to get the full 22 a/f needs 25.4 so the points will be slightly rounded, although i round them off anyway. They'll still look ok. to get pointy points (which i'll then round off!) pushes the price up ridiculously as we'd need to go up to 30mm bar and a heck of a lot more machining!"
So Loz, it sounds that your guy is cheaper but.... could you please make sure he will be using the recomended grade of stainless steel