OK, to bring closure to this thread.....
Basically, YIPPEE
This seriously works....there are a few YouTube vids on this but to be brief...for that is all that is required.
So, pressure bled brake lines and used INPA to bleed ABS: brake pedal went to floor - no resistance. Suspected MC had air in due to drain down of all brake lines,
NOW: To bleed MC in situ, connect a clear PVC bleed tube of appropriate length from the caliper bleed nipple nearest to the MC fluid chamber, to the chamber itself. Attach a filter of cloth or some such on the end of the tube (with a twist tie or rubber band) going into the chamber to filter any crud that might emanate in the bleed process. You'll have to remove the small plastic filter in the top of the chamber as the tube end must stay submerged in the brake fluid during the process.
Open the bleed nipple.
Now, gently, start regularly pumping the brake pedal (remember the vulnerability of the MC seals). As you pump a mixture of air and fluid will start to travel from the caliper to the MC chamber.
REMEMBER to keep the brake fluid topped up as you go as otherwise you will defeat the whole object. By the time all air (bubbles or longer slugs of air) is absent from the tube and just brake fluid is 'circulating' in this 'induction' process (for want of a better word) your brake pedal should suddenly be reassuringly firm again. If not you have problems elsewhere.
Close bleed nipple and carefully disconnect the tubing avoiding spillages.
Wow what a relief....like administering mouth-to-mouth and suddenly getting a heartbeat. To celebrate I did another pressure bleed and ABS bleed. Astonishing that a nearly 20 year old braking system can be as new. It's a real pleasure to be able to late brake and enjoy the drive so much more.
I guess I might be teaching some of you to 'suck eggs', as it were, but hopefully someone might find this useful. Who needs a MC bleed kit?
Thanks to Pingu and others for responding to my query originally.
Y'all!
Paul
I say Soanes - park the Z3 would you? There's a good chap.