There are a couple of pages on him in Nigel Brown Vol.1- London “British Gunmakers”.

Frederick Beesley was nicknamed “Inventor to the Gun Trade” and his various patents will be found in Crudrington and Baker, Volumes 2 and 3.

He seems to have made guns for others as well as in his own name.

Beesley Patent Lancaster boxlocks were I believe made (and perhaps finished) by him, and would be given a Lancaster serial number pre-fixed by the letter O to show not of their own make.