Simmons wheels - rim bolts

Hi All
I have been researching options for the 20 rim bolts on each of my V4 Simmons wheels.
What is the correct bolts - I'm assuming being Aussie it's M8 (and not 5/16) but the heads on these appear to be slightly too big and are a VERY tight fit in the wheel centre.
BBS etc use M7 which is an odd size and not generally available unless you purchase such bolts from Europe etc. These are available at reasonable prices.
Is it the case that these should be M7 but have been replaced over the years with the standard M8 variant?
Can anyone shed any light?
 

Well no as they're no longer in business and from what i've read the specs behind these whells is not readily revealled.

hey mate, there are still tyre shops that sell the simmons wheel nuts.. but they are pricey, something like $3 a nut..
maybe try contacting neale wheels?

Retro Wheels in Sydney are your point of contact. 02 9570 3033.
 
Don't think they'd sell you the nuts without them fitting them -  something about Duty of Care.
 
I looked to get the offset changed on a set I had  - they were helpful, but everything has to go through them.

Contact Pete West at The Mag Wheel Centre, Richmond, Victoria on 03 9421 1266. He's THE Simmons and BBS man! Cheers, David.