Wanted urgently - Axle Flange Bolts

Hi Guys,
 
I need 2 bolts (and the nuts) where the axle flange bolts to the axle housing.  (See pic below)
 

 
I have just finished rebuilding a diff and have been unsuccessful in tracking some down.
 
I got 6 as part of the Paul Dunstan R31 Bracket kit (the bottom ones in the photo) but can't find more.  I have even been to a few bolt shops and got some hex head bolts but because they aren't fully threaded they won't go in.
 
Out of interest the size is 5/16ths x 1 1/12 UNF.
 
Cheers,
 
Matt