To be honest obgraham I'm not sure anyone makes them. I just checked, they are 25mg !!!!! and cut them in half as I need them. They're in a blister pack and so it's obviously not a good idea to chop up a lot to avoid moisture ingress. I just cut a few and keep them in an airtight bottle. The doc didn't seem to have any problems with my methods.
So maybe it's possible to buy 10mg ones which is closer to the dose I take as needed.