I expect that I missed the original message because of my own inattention. That doesn't happen very often, but it does happen from time-to-time when I am a little below par. I did check the list archives before posting my message to Ralph, but his original message wasn't actually showing at the time: I believe that there is sometimes a small time delay between a message being posted and it appearing in the archives. Best wishes, Marion Woolgar Bognor Regis, West Sussex