So I thought I would give the network manager from Alien Bob a go in place of Wicd. At first it all seemed to be fine, but then today, whilst running an rsync session from my laptop to my server I inexplicably lost wireless comms. Restarted the services for it to happen again, and so on as a repeatable set of actions with network manager losing the connection after approx 20Mb uploaded.

I reverted back to Wicd, and have had no such problems since.

Problem is I am unsure how to go about determining what condition arises causing NM to fail, so any suggestions will be fully explored and reported back here to see if anyone can make sense of it.

Yeah, it does that - loses authentication during intensive traffic and can't recover.

I've built new versions from source regularly as new versions came out, and they've all been bad - until now. 0.9.2.0 seems to be ok But I've only been running it two days so far...

Edit: Well apparently 0.9.2.0 isn't ok. It just died, in the usual manner, damn it. Wicd is now being actively maintained, so we can close the door quietly on NM and tiptoe away... unless you need some of NM's fancy features.

No, I have no need for the extra features provided by NM. Who knows, maybe the WICD devs will incorporate similar things.
Thanks, at least I know it is not something I am doing wrong my end.