Apointment in London Lancaster's

[Alex Smart]

Hello,
Watched the film yesterday "Apointment in London".

The Lancaster's were coded "IH" was this a true Squadron code or a made up one for the film ? could not find it in Wikipedia.

Were the Lancaster's in the film all ex 617 Squadron aircraft as was NX782 ?

I noted also that she was photographed in earlier days in the "Tiger" colours with codes "KC" but for the film she is shown in the usual Wartime bomber Command Colours, black undersides etc, as are the other a/c shown in the film all with "IH" codes.
Was this code anything to do with the stationing and filming (?) at Hemswell ?

Thanks,
Alex