Well, you could risk a chance on them, there's a uk ebayer
here oh, some cheaper ones too
hereBit expensive, but then tungsten tips usually are, also they have a 3mm shank, which is the same collet size as the tool you want to get from Machine Mart.
I might get the same one on Sunday, (Clarke rotary tool) as Machine Mart sent me a Tax Free Sales Day letter, so ask your local Machine Mart if their doing a tax free promo any time soon.