Order placed, airmail cost more than the parts...

But thanks to the weakness of the Australian dollar it was still only £7.40 for 10 connectors including postage, which I can live with. The batteries themselves came from Australia as well, even though the website ended in .co.uk

So if anyone from the UK Googling for a JST XH balance charger female connector for a Dualsky XPower ends up here, I will probably have a few spare available soon.