thanks to everyone who offered constructive advice - intriguing what information can be gleaned from a small utility object like this. I did look in Thompson's book, and believe Schindler was a maker. I very much doubt Bernard that I cud teach anyone anything - but I appreciate the tolerance for a beginner like me, rather easy to get put off by so much detail - and I will remember your comments about mould-blown.
Thanks for the topic threads Anne, very interesting. Another book to get, I see!! cheers Paul S.