I never found it in the UK anywhere, so I eventually ordered a couple of bottles from Sharon's site. Then someone here on the board asked if someone could make something for them and I voluteered. She wanted to pay me, but I asked for some glue instead. She was more generous than I expected, so I doubt if I will need any more for ages.
It is available on ebay, but shipping adds up a fair bit, that is if you can find a US supplier willing to send overseas.