Is there a way to get it back up without power?
Can it be forced up? I'm not bothered if it doesn't work, I just want it up for now.
I'd really like to be able to use the car over the next few days and cannot get it in for a service.
All other windows work fine, its just the rear left that doesn't seem to function at all.

I checked with a multimeter, there is power to the switch on the door, so I guess the motor is kaput???

I guess I will just tape up the window with something for now... not having a frame over the door window is a real disadvantage in these situations.

So the regulator is dead?
If I buy and fit one of these, is that all I need to do?
http://www.ebay.com.au/itm/161166977524

Try giving the motor a good few taps with something weighty... Might be able to get a bit more out of the brushes if them being worn is your issue.

thank you, I hit it with a hammer a few times and it worked.

I had tried slamming the door really hard and hitting the motor with my hand, but a few solid taps with the hammer did it.

Thanks very much!

Weighty was a bad choice of wording. Solid is what you were after! Your finger and door was absorbing a good part of the impact.
Good to know it helped. Though know it will not last and you should get on a new reg (or motor if they can be done separately).