London Parish Boundary Markers

Curious the way this has been painted in two halves. As if half belonged to each house.... Also amazing that I've only recently noticed it as I've lived next door but one for 20+ years! I always thought these houses were built in the 1890s but as this marker is dated 1883 does this mean the houses must have been here then?

A clue for this gwl entry St Clement Eastcheap and St Martin Orgar. In Clement Lane by junction with King William St.

Once you've worked out the parishes should be fairly easy?