The Equality Act allows for single sex spaces and services to be provided, and states that this can mean that people with a GRC can be included or excluded depending on the situation and if this is a proportionate means of achieving a legitimate aim.
So, if I've understood correctly, this means there is a two tier system within single sex spaces and services, as some may include those with a GRC (i.e. inclusion is based on legal sex) and some may exclude those with a GRC (i.e. inclusion is based on biological sex).
How can this work in practice? Most things are mixed sex, but those that are single sex are surely only designated so to be a proportionate means of achieving a legitimate aim. What kind of situation would you have where a single-sex space or service would be based on legal sex (i.e. be mixed biological sex) and not fail to meet the original reason for why it was set up? How are women meant to know whether the single sex spaces and services they are accessing are based on legal or biological sex??