...In fact one cannot enter this street AT ALL from the other direction...
It may not particularly help the OP to know this but with the benefit of local knowledge, I can tell you this is a very common misreading of the signage.
This sign at the other end of the road doesn't prevent you from driving Northbound on Lowesmoore Terrace, it's actually advance warning that when you have done so and are nearly at the point where the OP entered the road,
you have to turn left.
In order to get to the other side of the junction where you can continue Northbound you actually have to turn left, turn left again, do a u-turn at the roundabout then come back to where you were, a round trip of 1.4 miles on some of the busiest roads in the City. The Council's stated reason for this is to reduce congestion and pollution, which to me suggests that in this case they are not so much venal and rapacious as they are comically incompetent.
If I can be of any actual assistance to the OP by taking local photos, I'm happy to do so.