The PowerWatch response starts off with a straight lie. They sell stuff for money. That is not independent.
He uses a stupid non-sequitur saying he is not a campaign er, but is qualified. I can't see why qualified people can't be a campaigner.
"Electronics and agricultural equipment"
Hmm, that's a qualification for understanding health effects of radiation is it ?
In other parts of the site he dismisses criticism on the grounds that they use "American spelling". Really.
In his own words he goes into the aluminium foil world, not the best defence unless you really have lost the plot.
Do a google on "mental illness" and "aluminium foil"
To be fair, if I was doing the tests, I would use large files. Actually that's not quite true, I know enough technology to do something that will ramp the equipment up to full load.
That bit of technology isn't completely trivial, since Wifi links actually spend nearly all their time waiting for something to do.
He shows that if you're far away from a phone mast you get less power. Is this not bloody obvious ?
He's flat wrong in saying A level students could not offer valid criticism.
I did the inverse square law at the age of about 13 or 14. By the age of 17 it is a reflex to anyone with any hope of doing science. The makers of Panorama seem to regard it as such advanced science that they can't be expected to hear of it.
It is such basic physics, that it is part of geography teaching, let alone science.
In his "equation" he doesn't quite explain what he's doing, but I can't for the life of me work out how he gets to the dose received by the child.