Cheers Ricky, I looked on World's End and found their prices. B&C look cheaper for better quality sprockets at least.
Regarding the gearing, I did a quick search and found a good gearing calculator.
I input the values for primary and the separate gear ratios and then changed tyre size to suit and also tried the two different changes I wanted.
So, stock (15/45)-



-1T front (14/45)-



-1T rear (15/44)



You can see the rev range doesn't drop too badly, and I only get a theoretical +2mph top speed. What I actually hope for is a slightly more realistic speedo readout, and a happier feeling bike for the road work I do.