I would like to say thank-you for the responses and the clear explanations given to my question.
I understand considerably more than I did a few days ago - and I appreciate the openess and willingness to explain to me the 'professional' view of what may happened.
I travel to Zurich weekly from Heathrow for my job. I could not ask to be more reassured in the professionalism of you people 'up front'
Thank-you.