No worries :) I live here so feel free to ask if you have any other questions.
I'm sooo tempted to recommend this place as it's quite an experience though maybe best recommended for when you don't have to go and sit down in a theatre for hours after, too much lovely food on offer!
http://www.bembrasilrestaurants.com/bar_and_restaurants.php
It's a great place, I hope you all enjoy it!
Ooh and as it's the Opera House if you are about Spinningfields beforehand then you do sometimes see some cast coming out of one of the side doors, usually for a ciggie break. Having worked right by it I've seen some of the cast of CATS and Starlight out having a cig in costume and even Michael Ball outside chatting and signing autographs. It's all a fluke as to the right moment and if anyone famous there comes out for cig breaks but worth a look. As you face the Opera House it's down the side to the left of it.
If you get down that area a bit early there is a Pret A Manger in the main Spinningfields Square (usually with an outdoor cinema screen up, sometimes on with news or sport) open until about 4.30pm (though Pret times can change a bit randomly at non busy times!) and a Starbucks opposite and up a little (towards Deansgate) on Quay Street where the Opera House is but on the other side of the road - near Tesco.