You will get an FM reception as the principle of radio is the same across the world, but the range of frequencies/stepping of frequencies may be different to those of a UK spec model.
I know Jap import cars have a frequency range of 76-90Mhz (and this is unique to Japan). The UK range is approx 87-108Mhz.
You can buy frequency expanders if you find that the unit you buy is too narrow or its stepping/searching incorrectly.
However, if you're looking to buy on ebay, pay close attention to the fees these guys charge for postage - its often ?35+, which when you add to purchase price doesn't make it that attractive - another ?30 would secure you a UK item with 12 months european waranty, and its intended for this market, so you know it will work.