It looks like it is a big chain, and I have only been once to the branch near Russell Square (http://www.patisserie-valerie.co.uk/brunswick-centre.aspx).
My wife has been a big fan of this place for years, and I was suitably impressed. It specialises in cakes and ice creams, with generous portions and reasonable prices. It also does lunches and breakfasts.
There was no music when I visited, and the place is also on a plaza a fair distance from the nearest road.
London WC1 1AF