Something else we should all ignore
We don't need to even wait for these limits to know that they will bear absolutely no relation to reality and be used merely as another stick to beat responsible parents who actually live in the real world. You just know what's going to happen:
1) Doctors and other health professionals will define what is perceived to be a safe limit for any given age group. In order to not appear irresponsible these limits we be set at an ultra-conservative level where there is no prospect of any adverse health implications at all.
2) The politicians will look at these limits, and using their superior knowledge of the human body compared to those ignorant experts will adjust the limits to 30% of whatever they were actually set at.
3) The Daily Express will hear about these new limits. Since their hacks are much smarter that the health experts and the government combined they will launch a blizzard of articles about how the government does not care about children's health and is encouraging underage drinking.
4) The government, seeing a wave of ill informed bad press, will pretend that the original figures were released in error and set new limits that are 30% of the already reduced figures. In other words, 10% of the already conservative figures giving by the experts.
5) Parents will see these guidelines for what they actually are and give them as much credibility as they deserve. However whenever there is any health issue affecting their kids the doctors will note that the kids are drinking more than the official guidance and accuse the parents of incompetence and neglect. Any future health concerns regarding the child are the parents fault for allowing them to drink at wildly excessive levels, even if alcohol consumption is not a factor.