.
CJ: I am not saying that the Ferranti family have never had a female flyer but .. my impression is that they have not. I did mention earlier in the thread that Denis de Ferranti compelled his aging driver to obtain a licence but I'm not sure if he extended this 'enforced flying service' to anyone else.
In my view the most likely candidate, and someone who fits your description and timeline, is Gay Absalom - the UK's first female commercial helicopter pilot.
If it was Gay who turned-up at Tern Hill and if she did arrive in one of Ferranti's Dijon-yellow 206's then this was perhaps by special arrangement and which is perfectly possible given that my godfather knew Gay.
Hopefully there may be someone with clearer recollections who can assist.
Sav