Noise from bellhousing - clutch woes

I've just done some work on my clutch, new disc, pressure plate, release bearing and machined flywheel.
 
After I'd reassembled it seemed like all was well until the engine heated up. At that point I began to hear a continuous squeel coming from the bellhousing, there was only a slight change of pitch when the clutch was engaged/disengaged. The clutch engagement remained smooth and operates perfectly regardless.
Having ruled out a clearance problem with the starter gear or release bearing. I pulled the box out again. No signs of metal on metal anywhere, pressure plate bolted down flush with the flywheel, clutch disc in fine condition but the flywheel looks like this

 
You can see the uneven burn marks. I've only got a couple of theories.

• Pressure plate not evenly torqued down
• Flywheel wasn't machined flat

But I'd of thought both of these would have meant a shudder in the clutch engagement.
Anyone got some new ideas?

Yes

My micrometers wont reach the friction surface of the flywheel . Thinking I'll take it into a different machine shop and get them to measure its flatness

did u take it back to them to get them to fix it or get your cash back?

oh well, atleast it should be right second time round...

Well FML.

All back together again and the noise is still there. It's noticably quieter however.
I bought some mechanics stethescopes and narrowed the noise down to the clutch fork.
I think the xtreme pressure plate I've fitted is not a perfect swap for the factory item. I think the clutch teeth must protrude a few mm further away from the flywheel at the point at which they make contact with the release bearing and this leaves them in the slightest of contact with the bearing, even when the pressure plate is engaged. I think it's quieter now because the flywheel machining I had done the other day took the flywheel/pressure plate mating surface down a fraction of a mm and this has brought the pressure plate further from the bearing.

I'm going to remove the slave cylinder and see if releasing all pressure from the clutch fork while it's running is enough to bring the release bearing a little further away from the pressure plate and stops the noise.

If this is the problem then I feel sorry for my release bearing, it must've gone through hell. Still it felt fine when I had the gearbox out yesterday.

Man doesnt really sound good...
 
Not sure if you can do it or not, but can you take the gearbox out and start the engine without the box on it at all?

Pretty sure it's ok to start an engine with no gearbox or flywheel on it, there are no major moving parts and I'm sure nobody would be dumb enough to y and touch the moving crank