Thank you for all the many kind comments. I'm pleased with this short series too and will take some more at the next show.
I am particularly interested in the discussion about the M's performance in these conditions. I think I agree with all the points made above, but especially the last one by Scheelings.
Basically, the real problem here is that (i) is was very low light and (ii) the light as it was was very high contrast - spot lights against black backgrounds. I shot at 1600 iso mainly, but some were still underexposed and had to be pushed often half a stop. I have taken a series of black and white photos in Rome with the M earlier, which I shall publish soon, where the black and white I thought worked very well and did not look artificial at all. I think the real difference here is conditions - not the poor performance of the M.
Whilst I agree that some of the photos have a bit too much of a 'digital' look to them than what I personally prefer, in fact this was an occasion where I felt I needed the M. I shot with a film M the same day, pushing Tri-X to 1600 iso. Only one photo was usable. The M coped much better as a tool than film for me in these conditions. Also, I have now made some A4 prints of some of these photos. They look good, crisp, clean, maybe a little too clean, but one thing is you don't see any digital noise - I don't think I could have got that quality from the M9, and I'm not sure my 5D MkII (which I have used for this sort of thing a long time ago before) would have done as well.
Finally, I tries out the MM for a while and whilst that would have been even better for this sort of thing in terms of high iso performance without noise, it seemed to me that the images were even more digitally clean and required even more PP to make them look like film (which is my preference). I had minimal PP on these shots. I did add a bit of 'clarity' in Lightroom and some of the Alien Skin Tri-X filter in Photoshop.
All in all, I think the M was the best camera for this job, and will be the one I choose again for the next show I do.
Nick