Note: Edited 17/12/13.
Many Cappos suffer from notchy (or even grinding) when changing into 2nd.
The very best treatment for this was Castrol SMX-S (fully synthetic) gearbox oil. It completely cured the notchiness for me, even on really cold mornings. It is now superseded by Castrol Syntrans Multivehicle 75W-90, which is (at time of writing) obtainable from Amazon UK, if you can't find it locally. Seems to work just as well.
The previous recommendation (Castrol Syntrax Universal) was only semi-synth, and couldn't hack the cold mornings, although it was better than anything else, and fine once it warmed up after a mile or two.