N gauge couplers.

You might get away with Peco couplers, no spring but available at reasonable cost. Otherwise Walthers in the US may be able to supply (my copy of their catalogue is currently on loan so I cant check).

Peco do then separately? Great. The mounting doesn't matter because I'm using them on my British HO by mounting them on a phosphor bronze spring wire under the chassis. A 3 link chain/iron dropper allows them to uncouple magnetically and they couple with NEM couplers.

I don't have one of those - by the time one is posted to NZ the price is about the same as a reasonable loco.

Thanks, Greg.P. NZ

You might try