I'm in Birmingham uk. The room is 12x14 i will be around 12 foot away. It will be plugged up to a tv via HDMI or opticaI for sound and one hdmi for sky would like to have Bluetooth. No blu Ray of anything else.
Congrats to your instant graduation from soundbar to a quality 2 channel system!
Back in the old days they did have a few small scale discount stores there, I am sure the new ones must be much bigger, like our Bestbuy stores in the US and Canada. If they do exist, just buy there and get the best deal you can, and avoid the individual dealers. You don't need any dealer advice, there are enough people here ready to help answer your questions.
Arcam is good stuff, years ago I auditioned their AVR300 and loved it. The AVR250's been discontinued long time ago so you probably meant the class G stereo SR250. If it is, I am sure it is a good choice but unless you can get one in the UK for a much lower price, it is a very bad choice in terms of value.
I know it sounds crazy to use a 9 channel avr, but the much more affordable Marantz SR6012 or Denon AVR-X3400H will get you just as much power, and in your relatively small room either one can power a pair of 703 adequately even if you sit 12 ft away.
http://myhometheater.homestead.com/splcalculator.html