Hi I did all this work a year ago but have not got round to posting it on here.
To busy enjoying it

Right this is how it started off, I have had my tv and all my Hi Fi stuff installed in the fire place for over ten years now ( I originally had a 25" Sony TV in place of the 32" Panasonic)
Sorry about the mess the little lad is wrecking the house.
First thing was to empty the whole cabinet out.
This is some of the wires I took out.
And with the cabinet taken out.
And how much space there was inside.
First job was to chase out the wall on both side and fit the concrete lintel.
I then bricked it up with solid concrete blocks and plastered it over when dry.
I'm not a plasterer
I left a small hole in the middle for all the wires and installed the plasma bracket ( £15 from E-bay but strong as a ox)
PS I now have a Kef 200c instead of the Paradigm c350.
Plasma in kitchen.
And when I first mounted it.
And how it looks after getting a plasterer to properly skim it for me and me to decorate it.
I know it's not a mega install but it was worth all the mess and the years of upgrading.
Now should I upgrade to a 60"
Dave.