I can recommend Whitewood too, we use them all the time and they're so reliable. Website not the most modern but the furniture is good quality. If you look on the David Philips website you'll see the same items with more modern pictures but they are dearer. They'll usually deliver to SE1 next day. We get the Capri Ortho mattress and have never had any complaints.
Think we bought from here online - www.mattressdirect.co.uk
deliver in the the next day or so - only to the pavement/front door - have to beg or tip to get them to go up any stairs