Had a look for a European supplier of potato starch that hasn't been heated above 140 degrees F, or whatever the magic number is...
I contacted Surya Foods about their Island Sun brand. A comment on the Free The Animal blog said they had confirmed this was raw. However, the chap on the phone said he didn't know the temperature because they simply repackage it.
Another member posted here that Rakusen heat their potato starch to 80 degrees C (176 F?).
I don't know if anyone has confirmed the temperature Kocken's potato starch is heated to.
DO-IT, a Dutch company, said their potato starch "has been heated with temperatures of around 150 degrees during drying." I got their details from Realfoods.co.uk, who sell this as their organic potato starch. They sell 1kg for £4.68, which is a fair bit cheaper than the prices I can find Bob's Red Mill for here.
I have compared the DO-IT and Bob's side-by-side in a glass of water, and they behaved similarly. Now I am past the headaches I don't seem to have much reaction to the Bob's starch, so I probably won't notice whether the other works or not.
Ocado stock a lot of Bob's Red Mill stuff, but no potato starch unfortunately...
Ocado stock Kocken's Potatismjol (search under 'potato flour' but it's actually potato starch). It has 80 cals/100g and settles like concrete at the bottom of a glass of water until you stir it, both of which things confirm it's potato starch. I've been using it all year.
One reviewer on the Ocado site is using it to starch her sheets!