With Susanne Beck“Letting them know you are here if you need me.”A visit with Mark Duffield at Upstairs DownstairsIntroducing a new column entitled “Behind the Counter,” featuring a salesperson, residents or visitors one would likely meet when shopping or just browsing around the Hill.Visitors to Upstairs Downstairs Home at 69 Charles Street are to be forgiven for doing a double take as they step into the store. The salesperson greets them, they swear they have seen him b