Ha! Me too...both our labradors have been hoovered today. Btw, a couple of things about miele bags; - there are fake ones out there. I bought some cheap off the internet and they weren't genuine and were rubbish. I get them direct from the miele shop online now - they aren't cheap so I pull all the dog hair out of a full bag and use it again.
Yes, hot air normal. I change the filter when the filter light comes on.
One thing with my one, it cuts out quite often (when you look at the control on the hose, it is still lit up, but down to standby mode), and you need to manually increase the suction using the control on the hose, IYSWIM. This seems to be a bit of a fault with them - I just sent mine off to get serviced, and the guy cleaned the electrical connections in the hose for me and this sorted it. Good to know it is fixable.