Issues with Airplay Mirroring

Hello,

Having issues with Airplay Mirroring to my Apple TV and I'm hoping someone may be able to help as I'm going round in circles reading other threads.

My partner and I have two Apple laptops, a Macbook Pro purchased late 2011 and a Macbook Air Purchased late 2012. We decided to purchase to the Apple TV so that we could mirror things from our laptops to the TV wirelessly, as we were getting slghtly sick of using a HDMI wire straight to our laptops (the lazy sort).

Purchased the Apple TV August last year and since then we've had bother. I first set it up on my mothers internet which hours after purchasing, the signal kept dropping and I kept having to either reconnect the ATV to the laptop or reset the router (BTHomeHub) to get it to work. We thought that this was just my mothers network playing up. We took it back to our house where we tried it on our internet hoping that the connection would be stable (our internet is VirginMedia and our router is NETGEAR). Again the same issues sometimes the connection would work and we could connect to the ATV, yet most of the time I get a silly error (on both computers) "An error occurred (-6722) while connecting to the AirPlay device “Apple TV”", However these error codes vary, sometimes they say "make sure i'm connected and the product is turned on."

I spoke to Apple trying to fix the issue and they said it may be something to do with my internet. I upgraded my internet to a pretty decent package and the bloke on the phone 'enhanced my wireless settings and signal' and said nothing more could be done really (Virgin media aren't the freindliest bunch). I fiddled for weeks and still we couldn't mirror through our laptops or our iphones with a cable plugged in and without.

Been to the Apple store today where as usual the customer service was superb and the lady swapped my Apple TV for a replacement thinking it might be the actual unit that was faulty, but oh no. Got home, plugged it in and again the same error and I'm still not able to connect to airplay reliably so i'm in need of some advice and routes in which to try.

Things i've already ruled out:
1. Done all updates on ATV and 2 laptops and my iphone.
2. Turned the firewall off seeing if the ports were blocked, no joy.

3. Reset router, unplugged and left for correct ammount of time.

4. Gone into my router settings to try and fiddle with the wireless settings and change wireless channel (under supervision of Mr. Virgin Media).

5. Used an ethernet cable from router to ATV

6. Unchecked the box in firewall settings.

I'm kind of out of ideas so I would really appreciate the help as all I want to do is mirror wirelessly from all our devices reliably.

Cheers, James.