I e-mailed them about five days ago, but never got a reply.
Join the club! (sorry no pun intended) I can think of at least 3 people (of the very few expat in France members) who are having the same problem, not a good advert for BPA.
To answer your question, when you register your piglets you have a second number which consists of your bpa tag e.g. TKX and then the number of the piglet, you have to opt for either your corresponding herd number, so if this is piglet no. 260 then its tkx260 or you can start separate numbers for your registered pigs, so that if this is the first piglet you have registered in that breed - then it becomes tkx1.
Of course it may have changed but I think thats accurate. Carole has just registered some of her tamworth babies, it might be worth asking her. I think BPA tags should be metal ones or tattoo.