Eh? New user session?

There's always things connected to it using the connection. So it's not really a time with no activity, just much less. And detecting a "new user session" can't be easy.

When real people, who care about d/l speed are using the connection.

Au contraire, it doesn't have to be detected, it's the time when real people (if you have any in Manchester) start to use the connection. Innit?

That varies far too much.

And using it at a slower sync for browsing is better than waiting for it to reboot. Also, if I was to reboot just before I get back from work there's a good chance I'll go to the loo when I get home, fucking the whole thing up.

I'm sticking to early hours reboots and manual ones if I'm really bothered. Since 4mbps is actually fine for casual browsing, just not streaming and torrenting stuff quickly.