I got an email from Dwaynne's photo lab, they're pretty quick, within 2 weeks of posting it out it's already on the way back. Prices is not bad $10NZ there and $20NZ back at current FX rates, slides are numbered and mounted (as I understand).

If you do 6 rolls together (max per the $15US return shipping cost), it's cheaper than using the main labs in NZ, but need to do some maths with Palmerston North....