Looking at this: https://find-and-update.company-information.service.gov.uk/company/01318739 you're just a couple of weeks too late. It looks as if the business has very recently been dissolved. A long time since I was in Chester but recall visiting the shop which was most interesting and I still have a couple of old catalogues from there. I would suspect that your gun would most probably have been made in the Trade and retailed by Monks. Lagopus.....