It`s amazing what comes into your head at 3 in the morning !
I went back to the 1871 census to look at other families in Fleetgate. Going to previous pages it shows The White Swan pub, next pages show a Thompson family with a butcher`s shop ; latterly there has been Thompsons furniture shop on the same side of the road., maybe the same family as the butchers. Counting the families up from the pub, I got to seven for the Milsons, so I looked on Showmystreet and I think the shop is the one on the corner of Fleetgate and Newport.
That`s if the enumerator was consistent if recording the houses consecutively.
Thanks for all those who`ve helped.