Thanks very much indeed John, that's a great help. Being a sort of 'quickie' publication, I had to rely on the info at my immediate disposal, and I must admit I had my doubts about some of the codes. I'll use this to correct the section, as I intend to post the complete groups of PDFs as one 'publication' at the end, or near the end, of the GB, so that people can have a quick reference guide.
Thanks again,
Terry.