This is the advice given by Semperit, the Austrian based tyre manufacturers, about overtaking snow ploughs :
"If you overtake, remember that where the snow plough pushes the snow to one side, a small bank of snow will form. Drive over this at an oblique angle to avoid having all your wheels stuck in the deep snow at the same time. Do not overtake snow ploughs working in tandem."
So apparently it's only snow ploughs working in tandem, which you should not overtake.
Mind you, I don't know whether they know any more about this sort of thing than the BBC.
http://www.conti-online.com/generator/www/de/en/semperit/automobil/allgemein/sicherheit/sicherheit_nebelschlussleuchte_en.html
And btw, local authorities advise appears to be very simular to that of the BBC. A typical example is this one from Poole borough council :
"Give snow ploughs and gritters plenty of room – overtake them with extreme caution and only if your overtaking lane has been gritted or cleared of snow."
http://tinyurl.com/yb3hpyw