The sprocket change from 45 to 36 has improved top end but not by enough. Two noticeable effects:
1: the rev limiter doesn't get a chance to kick in now in fifth but if I forget to change up it still works OK in fourth.
2: the bike just doesn't ever wind up to top revs with throttle fully open in top gear.

and finally after a couple of months my brain got working and logic says that must be a lack of power, it just hasn't got enough to carry the weight of me plus machinery even when wide open.

So is this a case where a jet change would work in my favour, i.e. more fuel? I assume just a larger main jet would probably do it and I will look that up and do it but I am wondering if experienced tinkerers amongst you think I would need a larger carburettor set-up all round, ie inlet size as well (and probably a muffler)? That lot wouldn't be worth the expense.