If you are in London and looking for somewhere "upmarket but inexpensive" to stay - take the Piccadilly line of the London Underground direct to Earl's Court from Heathrow Airport.
Travel towards the front of the train and you can take the lift straight to the street (the escalators, which most people use, are not easy with luggage - and take longer!).
You're then just a few minutes walk from the  base2stay boutique hotel, which has been excellently reviewed by me and other travel writers.
Singles £89 and Doubles £99 - and spotlessly clean.
Alun Hill MCIJ - IndependentTravelWriter.com