To All,
Regrettably my skills & knowledge are not at your depth. If they were, then I wouldn't have needed to ask the question.
I have also always been a believer that if you have a question in your mind then someone else probably has too.
Ergo, ask it, and get the answer and at the same time make the answer available to others.
In this particular case, I looked at Exit but not at Try-Finally. Why, I don't know, it simply didn't occur to me. I'm going to call it a Senior's Moment.
My thanks to those that have responded and clarified the issue for me and I unreservedly apologise to all inconvenienced by responding to my question.
I will attempt to do better next time.
Ian