Spent quite a bit of time today exchanging emails with the extremely helpful Ian from 21st Century Electrics. I got Ian's contact from the Homebuilding & Renovating forum I had spotted him giving out sensible advice there, (I especially liked the post that informed me cheapest place to buy CAT6 cable was ebay!!)
The pressure has been on to finalise what cables we will be running for future AV systems. We won't have much budget to add all the swanky boys toys to the system for a while, but know that the cabling needs to be in place now, boring yes, but has to be done. I have found it so difficult to get any sense out of anyone til today, thanks to Ian, I almost understand now the difference between CAT5 and CAT6 cabling, and what a 4x8 matrix can do for me!! Should have this sorted now by the end of the week (she said with fingers tightly crossed).