http://yesterdayfurniture.co.uk are based in Hackney I think. There's a couple of shops on Church St, Stokey - can't remember the name of one but it's near Il Bacio Express. There's also The Cobbled Yard behind the Daniel Defoe. There's 'Past Caring' on Essex Road which is a bit brik-a-brakie but is ok downstairs. There's a very good small shop on Essex Rd, where it meets North Rd (I think), next to the Taxidermy shop. It's expensive but it's genuine Mid-Century awesomeness.
A friend of mine had a book called 'Bargain Hunters London', here:
Thanks for this! Super helpful. :)