Hi Andrew, Not quite sure on the first question, I believe (but could well be wrong) that the 5 studs were fitted on very late 2002 S1 models, onwards. On the retrim, I had a seat done for £80 but that was supplying the leather which the previous owner had bought with the car - so right colour,etc regards T
According to "Morgan 100", the chapter on improving the Aero 8 states that the centre bolt was replaced for the Series 2 cars. Due to difficulties in torque management for the original set up. You might be right that there was an overlap.