Found that some of the Mapillary traces are from 2023, and show a new high-kerbed island on the Grove Lane exit, presumably to try to enforce what looks like an annoying and arbitrary L-turn-only out of Grove Lane (down to the big roundabout and back to get to the village!?).  Specifically, https://www.mapillary.com/app/?pKey=232492605955813
shows the new island, a car crossing into Grove Lane (the left only way added here seems to have been wrong), and (crucially for cycling NW-bound on the cycle route) an exception for cyclists against having to turn left out of Grove Lane.  Think I've captured this ok in https://www.openstreetmap.org/changeset/137201850
but feel free to tweak if necessary.