I have been looking for some specific sized plumbing fittings on trademe for , and noticed that there are overseas businesses from the UK, selling their products solely with imperial sizes. eg 3/4 inch diameter. I thought everything sold in the NZ market had to be in metric. Does anyone know if this is a legal requirement these days. To have things in imperial is confusing, and I suspect the sizes are slightly different as well.
You are confused about the strong demand for imperial measurements. There is nothing to see here.