We went to this today, combined with a visit to the annual Wildlife Photography exhibition.
It's not a huge exhibition but very well worth going to see. Seeing the tools from Happisburgh, dating from incomprehensibly far back, brought a lump to my throat. The Paviland skeleton and finds are also on display.
The exhibition is particularly interesting because (being at the NHM) it focuses very much on the fauna of the time, hippos, elephants, lions, etc as well as the human species that first colonised Britain.