Landlords beware. Duck and Hedges are the sort of company that will charge you for carrying out a Gas Safety Certification and actually not do so. I'm sure its a nice little scheme that they have running.
If you are a current tennant require a copy of your certificate you will need to wait until after the next inspection as they 'ARCHIVE' documents at are currently active (By Archive they mean that they don't actually keep these legal documents - despite it being a legal rewuirement to keep them for 24 months).
Their organisation is a joke.