Making QGIS layer update from changed .geojson data source

I have the same problem as Making QGIS layer update from changed data source.

However, I cannot get the solution proposed by Matthias Kuhn in a comment on an answer to that question to work.

I am using QGIS 3.4, I have loaded a .geojson file as a vector layer and am trying to refresh it without removing and re-adding. The map refreshes when I move it but the attribute table is not re-loaded.
I may not have understood how to use the reload function so here are my steps, I am using the Python Console.

       mc = iface.mapCanvas()
       layer = mc.currentLayer()
       layer.name()
       'radarOutGJTemp'  #--- Correct

       # Tried the following with errors attached
       layer.dataProvider().reload()
AttributeError: 'QgsVectorDataProvider' object has no attribute 'reload'  

       layer.dataProvider.reload('radarOutGJTemp')
AttributeError: 'builtin_function_or_method' object has no attribute 'reload'  

       layer.dataProvider.reload(radarOutGJTemp)
AttributeError: 'builtin_function_or_method' object has no attribute 'reload'

I can see the function reload appear in a window as I type. I did try to import reload just in case, that failed but again I could see it appear in the window as I typed.

import reload
ModuleNotFoundError: No module named 'reload'

  mc = iface.mapCanvas()
  layer = mc.currentLayer()
  layer.dataProvider().reloadData()
  layer.triggerRepaint()