Thanks Hugh .. I'll have to investigate using a bahtinov mask as on option!
Pete, the FWHM trick in Backyard EOS is live, except I don't have to rely on my eyes to tell me what's in focus.. by selecting a star and watching the histogram / value it can go sharper than what my feeble human eyes can discern (or so the theory goes!).
Thanks Kev! I did indeed neglect the flats. Which isn't forgivable shooting 5 meters from a streetlight really.
Thanks SimmoW!
Better / higher quality version here :
http://deography.com/wp-content/uploads/2014/09/M22.jpg