As a small side note, would anyone care to discuss just why it is that one would consider NZ a good place for pens of this sort in good condition?
I think there are a few logical reasons, backed up by years of seeing other people's bargain finds!
NZ was an important export market for CS from around 1920, and lots of their pens went down there, especially after the end of WWII. Although CS exported to many parts of the British Empire, the other main markets such as Australia, South Africa and India all generally have rather more extreme climates, so it would not be surprising that more pens survive in great condition in NZ. CS certainly considered the Australian and NZ markets important enough to produce a number of special models which were only sold in those countries.
NZ has a pretty small population, so I guess that there are proportionally fewer collectors and hence less competition for the pens that are still around. As well as the bargains I see that NZ-based FPB members pick up from antique shops, I have often seen interesting pens offered on the TradeMe sales site but again, competition for these is fairly limited because registration on the site is limited to the 'locals' in NZ & Australia. All very frustrating to those of us who live on the other side of the world!
I should add though that CS herringbone pens do seem to survive in better condition than many other pens, whereever they are found - the colours seem very resistant to fading in light, and the caps and barrels are not easily cracked, and remain glossy, for example. Having said that, the herringbones were only introduced c.1958, so they are also some of the youngest vintage CS pens around. The problems you see on them are generally restricted to the plated metal parts of the pens, which can be a bit weak in places and rather prone to brassing.
Andy