Umm, well I concede that it may be setting a precedent for advertising - albeit in a small way and for an obscure, minority product. Not that the countryside is free from adverts anyway - from John Deere on the side of a tractor to the T**co van barreling down the lane.
I've never really though about what Natural England do - or even noticed their existence before.
As for reading the site - well apart from the advertising issue it's mostly a list of rants about M**donalds, or "English Nature should be de-cluttering the countryside", etc.
Personally, I don't want English Nature or anyone else trying to de-clutter MY bit of the countryside by telling me to tidy up the spare lumber pile, or remove my ill-assorted plastic water butts, or remove the pile of rusty iron that I might restore to working order one day, just for the benefit of people who feel that the countryside is there to provide them with scenery.
On that basis I feel I'd be hypocritical to sign a petition to object to the odd small box on a fencepost.
just my point of view.
mab