I think you best bet would be The Sports Cafe. Go to www.thesportscafe.net and that should give you all you need. I'm a bit far outside of London or else I'd offer to buy you a beer (That's the honest reason, I'm not that cheap!) In case you didn't know the games start at 6 pm UK time with the Saints kicking off at 9.15 pm Monday will be a struggle. All the best and enjoy your trip.
Enjoy. There will not be a lot of Saints fans. Expect a lot of Steelers fans. Mostly friendly people and true NFL fans. No need to bring a body guard.
I will ask my wifes permission to go as well (watch this space)