Still haven't heard back from 2degrees.
Anyway, while I wait... I tried my wife's 2degrees sim with 022 # in my phone and so far I've not managed to replicate the same issues I was having with my 2degs sim with 027 # in it. Not sure what that proves other than its unlikely to be the phone that's the issue.
I have to say, compared to Spark, 2degrees mobile support has been pretty disappointing.