Was the solution! "Borrowed eight" metres of ethernet cable from work and connected the Apple TV to one of the "out" ports of my router and lo and behold, it works perfectly at the speed of light.
Well done that man, now off to buy a range extender ....
'Tis an option I have thought about but it would need to run along the skirting and around two door frames as we have hard wood floors. We would probably need nearer to 30 metres given all the routing. Cheaper (and I know it works) but Mrs ChasMill might object!
Yep, having a non 'n' device connected to a base station will drag it down. Some of the newer routers get round this by having 2 networks in practice, and using 5GHz for 'n'.
I've got the awkward to wire in 'study' on a pair of Netgear HD (200mbps) adapters, one in the easy bit of the house next to the BB router and the other in the awkward bit. They think they are doing something like 120mbps over my wiring.
One day I'll pay a sparky to fish cat-5 from the study across the house to the other side and save a quid a month on the power they use. (They are quite warm so must be a fair bit of power used to drive the signal).