Rocker cover bolts, what the hell are the head sizes?

As title,

Im now waiting on the Powerspark dizzy set up from simonbbc and whilst it is sat waiting I am going to whip the rockers off and give it a coat of looking at and hopefully cure the leaks around there that are somewhat dire to say the least, I have bought new gaskets and will order a new set of bolts from the bay of E in the uk, which come as cap heads which makes perfect sense but the current bolts have what looks like 12 point hex heads off around 8mm ish but can anybody confirm what the hell i will need to get the buggers out?

I know something around 8mm and bihex, funny, but the approach to the bolt heads are tight to and all my sockets are too wide to get in there, so any ideas on what i should be looking at as a way of getting the feckers out? is there a proper tool or am i butchering something up to get them out?

Help please chaps, im really starting to hate the V8, love the power when its running, the sound is fantastic but I knew my 300 so well this is like starting all over again, i feel proper lost

they are 8mm bihex

If you have a quarter drive socket set the 8mm mayfit. Or else fiddle on with a ring spanner

I believe they are 5/16" A/F, close to 8mm but the socketry for 8mm is sometimes too bulky to get into the cover recess..

I bought a 1/4" drive 5/16" A/F socket just for that job and it sits in the Bahco socket set.

Peter