What you haven't said (and may not know, ) was if the mini driver is to be prosecuted as well.
I can see the situation, two dumbos in lane two instead of lane one where they should have been, you are in lane one and go to overtake then correctly in lane three, when some smart-elbow comes charging up the inside, undertakes them and then pulls out into lane two travelling a lot faster than you. However, I suspect the police will take the view that if you knew somebody was behaving like an idiot, it does not absolve you from not taking that into account, when you pulled back into lane two - you should have made sure you knew where it was before you pulled back in. They may still prosecute the Mini driver!