My warmest thanks to all those helpful people who responded to my request for help, and my thanks to those who read my request, but for want of the specialised knowledge needed, couldn't respond. A little humour in repayment Two frenchmen walking down the Champs Elyse (spelling??) [anyway the main drag through uptown Paris ( Thats France folks)] and one said to the other "My god (in french of course) here comes my wife and my mistress" After a slight pause the other frenchman said (in french also)" What a coincidence" Best wishes from Philip Dunn