Hi, Thanks for the replies.
To answer your questions, my rear speakers will have to be very close to the sofa, probably about 20cm, which will mean if I'm sitting in the middle of the sofa I'll be about 1 metre away.
There is a gap of 2 metres between the sofa and the rear wall, but if I move the speakers close to the wall they will be the same distance away from the listening position as my front speakers are, which isn't ideal. I can't move the sofa back because my bed is behind it.
My rear speakers have front firing bass ports, so they should be okay without a wall behind them.
If you say your set up sounds good with 1metre stands then I think I'll get a pair as this seems to be the best solution.
Panasonic TX-32LZD80 TV, Sony BDP-S5550 Blu-Ray, Denon 1906 Amp, MS902 front speakers, MS 905 Centre, Mission 760ISE Rears, Atacama stands, QED Qunex 2 interconnects, QED Classic HDMI-P, Tacima CS929 mains block,Sound Style AV rack