Thanks Anne, Richard and Jim for all that information. And Richard, I appreciate that you very kindly did a lot of research on this subject some time ago and it was and is now very much valued. I believe you have the right comments and this clarifies things for me (who has been worrying about it on and off for the past two or three years!). Time to get enough data to be able to make a decision and then move on - or back. Thankyou all from Western Canada.