I'm a bit confused - why would having a Super-hub mean that the speed would be 'doubled' from 10MB to 30MB?
I've just been upgraded to 20MB, but VM called me a week or two ago and offered to upgrade me to a higher speed (not sure what speed) for an extra 50p/month - I turned it down because I didn't want a Super-hub, having read all kinds of horror stories about it. In any case 20MB is plenty for my purposes