The main survey was done on a dedicated survey website, I assume the netmums data was a supporting survey.
If you dig into this (and I did yesterday, along with a lot of other people as this was posted yesterday on MN as well), you'll find it's all a bunch of figure juggling with some scare stories.
The survey results show that most parents reduce their drinking post kids. Only 7% continue to drink daily. No questions were asked if this daily drinking was done in front of the kids, or if it was one glass or a full bottle, so we don't know if it amounts to excessive drinking. It was just a question about frequency.
62% of parents said their alcohol habits had no negative impact on the kids - which is fair enough, as it also says 70% of parents drink less than a few times a week. However, the charity makes a big deal out of and seems to think it puts 'parents' in denial about their drinking.
As to the class impact: the figures show that MC parents are more likely to drink daily (11% in MC, vs. 3% in Working Class), however, it also showed that MC drink less on average vs. working class (I believe it was 8 units a week vs. 10 units, or something like that). What does that tell us? Nothing, I would say, but the charity makes a huge deal out of this.
Then there is pages and pages of stats and case studies about the negative impact of alcoholism on kids, which we all know about and agree with. It's the stats leading up to that which are just rubbish.
Lies, damned lies, and statistics!