That's traditionally the 'Sale' period in the West End of London - so expect the shops to be overflowing with people. Speciality events are also thin on the ground after the run up to Christmas rush, (fairs, shows, etc.)
However - I'd say that's an excellent time to see London, there are lots of ideas on the site I edit - #mce_temp_url# of places to go and things to see. All the attractions have either a google map or postcode listing, (which you key into a UK Google map search) so they are easy to find. There are also feeds which show specific events which will be occurring during your visit.
Patrick