Thanks - didn't spot the arrows on the traffic lights.
How about this? https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=55.95434%2C-3.18753%3B55.95385%2C-3.18606 Do we have any evidence that this is illegal?

Also in front of the Scotsman hotel it says "BUS TAXI 🚲 ONLY", maybe this is meant to apply to this whole stretch of the road? https://www.openstreetmap.org/directions?engine=fossgis_osrm_car&route=55.95330%2C-3.18890%3B55.95272%2C-3.19221#map=18/55.95315/-3.18968