Langleybastion-I may have some good news for you!
Duxford's Lancaster (in AirSpace, not the BBMF one) is open to the public during half term. You can get inside for a look (about as far as the aircraft code letters) fo a short period.
I believe it is open on the 24th at Duxford if that helps? Edit-confirmed-see the link below.
http://www.iwm.org.uk/events/iwm-dux...ter-experience