Unfortunately there is no set rule about surface area, probably because no one can agree on it! Surface area is very important though and I would never recommend this sort of overpriced crap tank to anyone. 15 minutes a month, my arse. Any owner that only takes that time to look after their pet is neglecting them.
You could alert the RSPCA about it, the 2006 Animal Welfare act applies to all vertebrates and by law the owner must meet-
(a) its need for a suitable environment,
(b) its need for a suitable diet,
(c) its need to be able to exhibit normal behaviour patterns,
(d) any need it has to be housed with, or apart from, other animals, and
(e) its need to be protected from pain, suffering, injury and disease.
You could argue that point a) is not being met but it would be a tough argument because as Queen said, people just don't care enough about fish to make a big deal of it :(
And you would have a tough time finding an expert because a lot of them work for magazines or aquatic firms and they seem to be more concerned about money than fish welfare (a quick look at all the poxy 'toy' tanks that are on sale shows that).
Basically, the whole industry is fucked. Can you tell I'm annoyed about it? 