I bought a wireless multi-room audio system two or three years back. You get a little transmitter that plugs into anything with a 3.5mm audio jack (or phono, with the right adapter) and you get two independant speakers, which can be used in different rooms in mono-configuration, or as a pair of stereo speakers at the flick of a switch. They run off six AA rechargeables each (built in charging system) so are plenty loud enough, and the whole setup only cost about 35 quid, so this seems like incredibly poor value to me.
If you can find the right model, one of those RF devices intended for a car will work reasonably well once you have soldered on a sensible antenna.
So, do you think I am going to be spending £350 to get a slightly worse setup?