Thanks guys. Yes, Ken, at 50mm focal length the LXD-75 does a good job without any guiding (up to 2 mins in this image). Focus was close because I used MaxDSLR focus software to check.
With regards the filename system: in less than a minute I can find on the hardisk any of my raws, intermediates or final versions of images - and tell you their scope/lens, exposure details, filter, date, guiding, screen dimensions, etc. ...
(I'm too cheap to buy some software to do this
).