A friend of mine is selling her son's tenor horn - it's a round stamp Sovereign. She bought it second hand from Yardley's of Birmingham (anyone else remember them?!) I've offered to put it on here for her but would like to try and date the horn (the production!) so as to be as accurate as possible when describing it for sale. Could anyone suggest a website I can go to to find out the info - I've Googled "dating" and "my horn" and didn't get the right sort of site Any help would be appreciated. Thanks,Phil.