Fire
Wing Leading Edge (Port side by the look of it) impact with the radio mast may have ruptured the fuel cell (Even though CAA Special conditions requires a strenghtened leading edge modification to be embodied to UK registerd Cessna Citation Types). This could have started the fire rather than an engine fire occuring earlier on the approach. Note from the pictures that the most intense area of fire is around the Port Wing.
Wondering how the aircraft ended up so far off the Centre Line?
Even with an engine out, with light winds I can't imagine an asymmetric approach and landing resulting in a collison with the Mast.
Nav Receiver Localiser calibration error, FMS error or LVP issue maybe??
AAIB report will make interesting reading. Hope we can all benefit from lessons learned.
However, all that matters though is that the crew are alive!
Wishing them a speedy recovery.
Good Luck for the future guys!!