Ok, I'm actually in the garage typing this, connected via an ethernet cable into the AEBS which is connected via the Solwise Powerline.
This proves that the powerline is giving the signal at least.
I set up a different wireless network to see if that would give us any answers, my iPhone could see the new network (as could my laptop) but after joining neither could get an internet connection.
I will attach the AEBS settings to see if I have missed anything but I think the problem has to be in the powerline, no?
note; the channels are on automatic at the moment (I have had these on manual also) as it took the 5ghz up to 100 (which I do not get the choice of even with the option key held down).