Why yes, yes it is... except you're comparing the figures USING A DIFFERENT RATE OF TAX!
Jesus, how hard is it for people to understand simple mathematics. If you want to compare what APPLE is charging you then you need to compare pre-tax figures, end of story. You can't bitch and whine about Apple (or any company) charging more in the UK because sales tax in the US is 5% and the UK is 17.5%, they don't control that figure and can do nothing about it.
So using your figures you need to convert $829 to pounds which would be £560 leaving a £35 difference. However you also have to consider that the cost of doing business in the UK is higher than the US (building costs, transport, electric etc etc) which tends to work out around 7% additional costs to Apple which would be.... £39. Gasp shock horror. So no, actually Apple have priced the device almost exactly the same as the US model once you take the tax and overheads out of the equation.
Oh, and just for the record, yes you can buy in the US but you should really have to include VAT on top of the price as importing a device without paying tax is technically smuggling and illegal.
Come on folks, every time a UK price is announced we get people complaining while unable to calculate the difference properly. I accept that someone in, say, the US could look at our price and think it was a rip but if you live in this country please please please educate yourself about how our tax system works before complaining, it's starting to get embarrassing.