The reason for the different chair was the arrival of Ryan their second child and two seats were required, note the buggy which clipped to the side of the chair using ½ inch pipe clips.
The down pipes are not rusting or dirty but covered in oil, running at a 20 to 1 mix it seemed to shove oil out of every known hole on the bike, however small.
Later on, the same chair, fitted to a Jawa (Rotax) 500. The engine was superb, unfortunately everything around it either fell off or packed up. Lock tight was the order of the day, along with a spare chain. It got nick named "Slack Alice" as the chain would always be slack when you parked up. Lesley, Martyn, Cheryl and Ryan went to Martyn's sisters wedding on this wonderful machine, needless to say Martyn's sister wasn't impressed. The roof rack was for carrying floor joists when they built their house at Soham.