I just stayed at a MINC appartment off Fleet St (walking distance to Covent Garden). 2 bed, living room adn kitchenette was 200 quid a nigh, i bed would be cheaper. Wouldn't want to live there, but was what I needed, with a 24 supermarket 2 minutes away for supplies
Anyone recommending the Strand Palace needs a good talking too. The Waldorf is ok, but expensive. Thistle at Charing Cross is souless (but you don't need a soul for a night). Hilton at Trafalgar Sq is what I would imagine an Eastern European brothel in 1975 would look like.