Question Author
Well done everybody, you've solved this in my absence. The actress in Come Fly With Me and in several of the Boots ads (one thinking she's dying, another insisting on telling people the Christmas presents she's giving them as she hands them over) is indeed the actress I was after. I've just seen her in the CFWM episode and it's clearly her.
Incidentally, for those who saw that CFWM episode, the actress playing the nervous passenger being told how reliable (not) planes are was Annette Crosbie's daughter,Selina Griffiths.
Not a lot of people know that!