Well I've just been on the phone to Martin at DRAIS in Croydon - most helpful chap (Hi if you do get to log in here Martin...)
I was calling to talk about getting my (probable) H/HGF looked at and he asked how I'd been bleeding... and said he'd never had any success with the old see-saw method - He reckons the big problem is getting air out of the back of the block and through the thermostat.
Now guys heres my post call notes - may have got some details wrong and before I attempt this later (when I get home) would love to hear your thoughts...
- Drain enough to get the rad cap off.
- Set the Rear HM to HOT and the Front HM to COLD (this because the front HM is higher than the rad)
- Run the engine till hot - he said "this isnt quick, run it for hours" - hoping he was exaggerating a little...
- Fill from the expansion tank - watch the bubbles at the rad cap
- Once it's stopped bubbling, cap off the rad
- Now identify the host coming straight out of the thermostat housing that goes to a pipe that runs back to the Rear HM. Clamp the hose and gently/carefully disconnect the hose from the stat housing (water will be hot!) - have someone keeping the tank topped up or leave a hose running gently
- Water will gush immediately but that flow of water will allow the stat to open and the flow will change...
- Replace the hose quickly or air will be drawn in... and then unclamp.
but let us know how you get on 