Well, firstly it is not a resource pack. There are no resources in it for use within a school.
Secondly, it is propaganda, just as much as many pro transgender leaflets are. It is well written and thought out but statements such as the below are hypocritical, especially in the context of advocating open discussion within a school environment:
'• Gender: Masculine/Feminine Societal expectations of behaviour, aptitudes and appearance depending on sex, which change from culture to culture. Gender or sex-role stereotypes'
This is merely an axiom that the pressure group believe in, and in no sense uniformly accepted by the scientific community.
It is also extremely arrogant and didactic with 'advice to SLT' as if SLT members are idiots incapable of formulating a policy without the 'expert' advice of a pressure group.
I think it is good for a group like this to exist, good for them to come in and talk to schools and give their perspective. However, whilst excellently debunking their opponents, they are not prepared to admit their own bias and have made their material look as if it comes from the DofE and look like officially sanctioned advice.
It is a shame as I suspect it will get binned and there are many good points within it.