At the weekend I tried a pack of Orgran GF buckwheat pasta that had been in my cupboard for a while, and I liked it. I noticed that the company is Australian, so I emailed them to ask whether their products all meet Australian standards, or whether they do a 20ppm version for the UK.
This morning I have received a very detailed and helpful email back, explaining that all their products are made in Australia, to their "no detectable gluten" standard. Although I don't usually like buying food that has come half way round the world, I am about to make an exception and stock up with their pasta and flour and possibly some crackers. Their large range includes some packaged breakfast cereals which don't interest me because I avoid added sugar, but they may help other people.
I found them at orgranglutenfree.co.uk and orgran.com