According to Nigel Brown's book on Birmingham Gunmakers he lists someone cvalled Grant Dempsey of Broxbourne, Hertfordshire Telephone 01992 462742 as having details but as far as I am aware they were then sold on to the Royal Armouries Museum in Leeds who now have them. Brown's book lists serial numbers to year date which may help but for full records try e-mailing The Royal Armouries. I do know that the odd book is missing from the records though. Lagopus.....