Hi,
Well after I'd patiently waited 18 months to hang my Plasma on the wall, it's done!

The room is still not completely finished as I am awaiting a leather corner sofa and some other furniture, but I thought I'd share what I have aready done.
I didn't want to channel the cables into the wall as I plan to ugrade my equipment and as a frequent visitor to this forum, it wasn't hard to find inspiration and helpful tips. I wanted the false wall to blend into the room so after building it I re-coved and re-skirted it to match the room.
The construction was a simple timber frame screwed to the wall, plasterboard applied to that and I then plastered. I attached the actual plasma to the brick wall and created an alcove so that the plasma would not stick out too far - I have the older Panasonic Viera PE30 and to mount it you need an additional spacer pack. This worked really well as the plasma now appears to be just off the false wall while not blocking the ventilation panels.
The unit was not the original one i had in mind, but with a recent trip to Ikea my wife saw it and we instantly thought that it would work. It is part of a new range called Besta (I think!) I just modified it slighty by not using the back panels and by buying the Chrome legs. In total the unit cost £36, which I thought was a bargain!
Please if anybody has any questions, fire away. I hope this may inspire or help other people thinking of doing similar things, just as other threads have helped me.