Not George but another Brit who also rates this thread, here is a link to the makers site, Fujix which though it has its international offices in Japan seems to have its threads spun in China.
http://www.fjx.co.jp/english/catalog/index.html
and the link to a British distributor,
http://www.somac.co.uk/kingstar_thread.html
it's mainly telephone sales but they really are nice to deal with, no pushiness or flannel.
Then there's this one who I havent purchased from,
http://www.dowlings-sew.co.uk/products.php?cat=245
There are others which if you Google Kingstar threads, then ask for UK pages only, will come up.

I have had such good service from Somac and found they have the best price list, which is not displayed on the website, that making a phone call is a minor worry.
They offer a trial pack for £5.50, which includes 1 metallic,2x poly 1000m cops, backings, a couple of pre wound bobbins, which unless you know your bobbin case size you wont use, and the shade card. I keep looking at mine and salivating. Sad woman arent I, but I cant afford the 600 colours in the 5000m size and am slowly building up my 150 1000m cop collection.
Maggie in England.