Their main online store has pricing in US dollars, and the software's $499 (minus 10% until January 10th, for what it's worth).
Unfortunately, they won't let people based in the UK order from that store; you have to order from their UK store, which has the same software for £419 (and no discount). For those of you playing along at home, £419 is currently converting to $791.
So, let's see. This is software in the same language (so, no localisation issues), which is downloadable (so, no shipping issues). Apparently I'd get tech support from within Europe rather than from the US, should I need it, but given that I routinely deal with people in several foreign countries for tech support, this doesn't really stand out as a selling point.
How convenient that rotwang is going to the US next week.