Hi there Dupre,
Firstly, the £30,000 modular course I mentioned involved getting the CPL/ME in the US. It wouldbe more like £40,000 in the UK, so you're looking at saving ~£18,000 by coming over to the UK with your NZ CPL/ME. Believe me it will be cheaper than doing it in the UK.
These figures are real finger in the air stuff so don't take anything as gospel
From your description of the NZ market for twin GA, I think it's not a million miles away from the UK - there are very few opportunities for ME hours in GA here.
cheers!
foggy