everything I'm hearing is that the single sex exemptions bit was genuinely fought for and won by the GC wing of Labour, and that the manifesto is intended to seek a middle ground by making it easier to get a GRC but at the same time beefing up the exemptions and limiting what entitlements a GRC confers.
That would be a step forward, depending, of course on what limits are set on the entitlements a GRC confers. But I don't know how they'll get round this conundrum:
'Female' is, by definition, a sex marker. If any male can self ID as 'female', single-sex provision for females will inevitably include males.
A better solution would be to repeal the GRA since it is no longer required: its main purpose in 2004 was to allow same sex marriage by another name in a form which was acceptable to homophobes.