[FiscusFish]

Trust Frank to be Captain Sensible.....

Here's a picture of the bottom of my SL seat base. There are no extra mountings on the frame.

Bare in mind though that even on genuine Superlights the base will rub on the rear light lens if you don't get the position just right when you do the screws up. Some carefull bending of the brackets generally puts a stop to it.

Darren