The Airfix model was created from a laser scan of XL231 at Elvington. Airfix made one error on the B2 model by incorporating the rear underside flood lights which were fitted to the K2 only. Also, I wonder if they realised the B2 had a wingspan of 120ft which was reduced to 117ft for the K2? The B1's was 110ft for anyone thinking of modifying the kit.