Hi Georgie, I found your post after googling Opawa Playgroups. We're moving from Wellington to Christchurch next week and are also going to be living in Opawa. I'll let you know if I come across any playgroups that look good, and it'd be great if you could do the same?
I also came across the Opawa St Martins Toy Library which looks good, but it hasn't reopened yet since the earthquakes.