Is it time to start calling out bad cyclists?

Because filtering on the left of a large vehicle is a very stupid thing to do. Filtering on the right is better practice all round - motorists are much more likely to be looking for trouble on their right shoulder than their left - and has the advantage that you avoid all the nodders filtering on the left.

Yes, that was what I was going to tell him. Thanks for explaining it to me.

As it 'tell him why you shouldn't filter on the inside of a large goods vehicle'