Classical concerts - London
 

Havent been to a classical concert since I was at school (around 15 years ago @ the Royal Albert Hall) but more recently I have an urge to hear some live in a half decent sounding venue.

So my question is where in London can I go to hear some Bach, Elgar, Tchaikovsky etc. that isnt going to cost me an arm & a leg?

I am not worried about seeing named performers reciting the works and would rather go to 3 or so cheaper concerts rather than 1 fancy expensive show with a well established name/names.

All help is appreciated!