The vacuum was rattling strangely so I did my weekly clean up.

The main brush freely spins if I push it, this was not what I remember as it always had resistance. 

I put it to vacuum and the main brush does not spin, evidenced by a piece of string not being touched since I can't really see under the vacuum when it is working.

So it seems that the main brush is disconnected from its motor.

What options do I have to fix?

I'm quite happy to take apart to fix it but I'd appreciate a manual so I don't damage anything in the process. This is after all scrap if the main brush doesn't turn.