Coming back to this after a wee while!
Tony, thank you, if you have a larger version that'd be even better as I can clip out each piece and show the detail better.
Tony, does your advert have a date by any chance? I'm trying to run to earth who may have been the dealer at that address and a date might help. 11 Ludgate Hill was a building which had multiple occupiers, including Dean & Co, the publishers; a photographers; and several general merchants.