Just a few points of confirmation, the Lanc is a standard MkVII, notable by the mid-upper being in the further forward position over the aft escape hatch. It wears the Tiger Force scheme, so probably isn't a maritime aircraft, (you can see the black undersides just extending up towards the bomb-aimer's blister.) The aerials on the nose are the Rebecca blind approach aerials, standard on all late war /post war Lancs. The thing sticking out from under the fuselage is indeed the trailing aerial mount. On very early Lancasters it was on the other side of the fuselage and further back.
The code letters are difficult to pin down, but the exhaust staining is pretty normal!