EBC Heavy Duty Springs.
So after a few rides on the old 550, it soon became apparent there was a bit of clutch slip when used hard in high gears, but the main issue (for me) was the clutch lever was just too light. To the point that when you were trying to get away from the lights, especially uphill, the clutch just wouldn't bite fast enough.
So Wemoto quickly sent me some new springs, and a Slinky clutch cable in case the old one couldn't take the pressure. These guys are amazing, great prices, very quick and efficient service!