Hi aintenoughwiskey!
I believe it's basically the 'exempt occupations' principleIn this day and age how can the WT discriminate against women and still maintain charity status?
Think if they had to do TV and theatre casting with no discrimination of sex, race body type etc? haha
That's why audition notices are exempt from this type of legislation
https://www.backstage.com/casting/finians-rainbow-129154/
https://en.wikipedia.org/wiki/Equality_Act_2010#Exempt_occupations