The basic point is that she wanted to go right. If I had been going straight on or left, the chances are I could have smacked straight into the side of her. Mercy had it that I was also going right so we were BROADLY travelling in the same direction.
Whatever the semantics of undertaking in slow moving traffic, it was at a junction and it was only slow moving as I had slowed for the Give Way.
And my point was made to illustrate just WHY some motorists treat us cyclists so badly – they see that sort of riding and assume we all ride like c*cks.