Got it, will keep that in mind for the next one I try, thanks!
Totallymaxed: can't comment on whether the display drivers were working correctly (no way to tell really!), all I can say is that the exact same laptop, with the exact same PXE configuration stuck in a reboot loop before I tried to add the MD to the Admin console - (1audio: I note that it was well into Linux boot, having already done several pages of logging on the screen, including changing the font, so there is no indication of a PXE issue, it gets well past the PXE part).
As soon as I created the MD manually (as a device, directly, not using the specific Add MD function, as that didn't work as already described) and rebooted the laptop again, it worked perfectly.
Nothing to fix here for me, I was only testing using it, I am not attempting to get it working permanently, and have now moved on to testing other stuff - just thought it might be of use to someone else.
ok just a footnote to this then - adding the device manually in our experience can often leave you with an MD that looks like its been created fully and is working ok but in fact often is not. It seems like some of the scripts that get run during and after auto-detection do not complete properly if a manual add device is carried out. I can't say what exactly fails in this situation but it is our experience that using auto-detection is the most reliable way to add MD's in particular.
However your mileage may vary ;-)