"Also hard to see how to safely access the pavement lane northbound."
As a fit, assertive cyclist on a standard bike, I'm not going through that mess at the moment.
I crossed from the road to the pavement lane at the pedestrian crossing outside the John Lewis entrance, but I think that doing the same at the Leith Street traffic lights when it's either on a right turn or green man way also be the only way to safely get to it Northbound.
Rejoining to continue Northbound at Elm Row means coming off at Greenside Lane by the Theatre Royal, crossing during a break in traffic into the coned off middle road then coming through the cones onto Elm Row.
Cats in an earthquake indeed.