Those instructions are for logging in as Administrator, not SuperUser. Bearing in mind that the SuperUser account password is the same for all O2 routers unless changed, does that mean that a security hole still exists?
I put this to o2 and this was their response.
Any software security system can be cracked. There are many password cracks posted on the internet for many makes of routers. Please remember
the liklihood of this happening to you is still very small. The most common thing to happen is people using your broadband service, but if you
have wireless encyption this will prevent that.
Ensure your firewall is on your router and that its on your computer too. Update anti-spyware and anti-virus. If you have changed the password
on your router and use wireless encryption this is good enough. Having many layers is the key to good internet security, these consist of
1. XP or Vista password
2. Router password
3. router hardware firewall
4. wireless encryption
5. PC software firewall
6. PC anti-spyware
7. PC anti-virus
8. Internet explorer phishing filter
Remember the most common criminal activity is phishing emails and most hackers tend to target organisations and not individuals.
Hope this addresses some of your concerns.