One google search, but posted here to keep forum community chat going. 

I could go off and completely find all Apple stockist and ring around, but the where is the fun in not posting a thread to GZ in that

Linux: What research have you done yourself?

Unfortunately, Apple doesn't offer trade-ins to us. But it does look like both Spark and Vodafone have trade-in options.

I think your best option would be to sell your device either on Geekzone or Trade Me.