It's not the slow lane, it's the inside lane, which tends to used by slower vehicles.

Middle lane sitters force cars out into the overtaking lane where the motorway lunacy is at it's worst, with owners of penis substitutes hurtling along at insane speeds.

No offence meant to your good lady bubblyrat, but there is no excuse for middle-lane sitting. If you can't deal with cars joning the carridgeway at a junction then you are not capable of driving on a motorway - countering the poor behaviour of other drivers with equally poor behaviour is madness. The system breaks down if everybody just does their own thing.

There are dubious contraptions all over the road network, mud on virtually every road etc etc. Learn to drive properly or stay off the motorway.

You're right about the spray though. Then perhaps I too would sit in the middle lane if it was just wagons on the inside lane.