You've mentioned the hub drops out. Do the lights change when this happens? Are you losing wireless connection or does it also happen when connected via cable? If it's wireless issues have you tried changing the channel? Can you give us as much detail as possible and we'll do our best to help.
Since my original post BT have sent out an engineer this morning who has conducted a series of tests and also changed the Hub. I am still having the DNS problem but not as much as before. I should add that I never had this problem when I was with Sky so suspect it is not a problem with my laptop.
I have not connected with an ethernet cable as the laptop is still connected to the hub by wireless, it just doesn't seem to go past the hub. The light changes from blue to a steady orrange when it drops out but again this is not happening so often.
I have flushed the DNS on my laptop which didn't really make any difference. The one thing that has changed although not sure if it is relevant is that the WPS now works on this new hub.