Ah, well, in that case some of the UK retailers may also be a good bet, as per prior posts.
If all you want to do is maintain your regular razor, then you could go with a Norton, but when I went hone-hunting, I decided that if I'm unlikely to use the 4000 side at all, and I can get a finer stone, I'd rather do that. All you need is a barber hone, or a finishing stone like a Naniwa 10k or something.
I just got a barber hone, and I've excited to give honing a try for the first time in a little while! Hope I don't mess it up... :)
But don't worry about that yet - you shouldn't need it for a good several months. Just focus on learning shaving and stropping.