NZ won't accept a British Instrument Rating. I brought a fully valid 747 /ATPL but they wanted me to start an Initial NZ Instrument Rating on a twin something. NZ Instrument Rating can be built up bit by bit, i.e, an I.R. that is valid for ADF only, then add VOR / DME approach,then add ILS etc.
I told them to get stuf--d and was given a VFR only CPL -all I needed to fly as a volunteer Coastguard Patrol pilot on a VFR only Cessna 182 anyway, so didn't fight it at my age !
NZ doesn't have Group type ratings, either. Every type has to be individually written on to the licence, no such thing as Single Engine Land, or Mult-Engine Land. When you apply to convert to a NZ licence they will add every type that you can show logbook evidence of, to your initial licence, after that it will cost $100 per type to add. I got a PPL initially ( long story ) and made them add 707 and 747 -just because I could !
Did once ask if I could fly a 747 under microlight rules ('nother long story ) but was told that microlight rules only allow 1 pax. so did I want the co-pilot or Flt. Engineer (I never flew the -400 ) Bureacracy does occasionally have a sense of humour !
Best of luck.