In the original build the two separate 'attic' rooms were for the House Keeper and Butler, whilst the interconnecting rooms were for the scullery, kitchen and other young maid servants who made up the domestic staff when this place was first occupied. Census returns indicate that the Butler's position was soon swapped for a 'Head Cook'. Typical of its type - being built for show and on limited finances, the construction was typically poor and the condition of the building today reflects this. A delve into the records of the planning applications associated with the conversion to flats should give more historic details, should anybody be interested. This building is well known to those of us who were interested/involved in the preservation of large Georgian houses in the 70's, when many were standing empty or being demolished because of death duties.
The fact that you find almost identical designs of windows, doors, ceiling cornices / plaster work in all Georgian period properties, is due to the fact that the prominent architects of the day published books containing complete details of their designs. Thus the local jobbing architect in any small provincial market town could draw up plans that replicated buildings seen in the major County cities. Sadly construction methods in these inner town or city Georgian terraces were sometimes very poor - an apt description would be Jerry Built. Many years ago I had a flat that consisted of the whole of the first floor in a Derby Georgian terrace, my sitting room was what would have been the principle bedroom of the house and it had a very springy floor. One day whilst helping my landlord fit a new ceiling rose in his living room we had to lift the floorboards in my sitting room and the reason for the springy floor was revealed. Instead of the floor joists being a single length of timber spanning the interior walls, most were made up of two length joined by a overlap joint held by hand made 6 inch nails. As the terrace of eight properties were built, when the builders reached first floor level they just laid lengths of joist timbers along the whole length of the terrace, overlapped each joint by approx one foot and banged in half a dozen six inch nails. Jerry building and building on a tight budget at its best. However with its cast iron gates at the top and bottom of the street, good old Hartington Street must have been the in place to live when it was first built.