‘We have moved’ could be interpreted as the staff having been relocated to the existing shop at Daunt Square –so the P.R. Department can rely on this interpretation if they need to defend the accuracy of the message.
‘We have moved’, I suggest, would be interpreted by most as movement to a new premises – closing one and opening a new shop, bigger or smaller. This is what would be the wording on the building of an enterprise that did indeed move to new premises.
Any visitor to the city reading the sign, or anyone not aware that the Daunt Square premises has been in existence for many years, may very well assume that a relocation to a new premises – a assumption that the P.R. gurus may well be happy not to dispel.
My own preference would be a straight talking sign along the lines of:
Our staff have transferred to our shop at Daunt Square.