I thought there weren't any exemptions in the EA that relate to gender reassignment.
It's here: www.legislation.gov.uk/ukpga/2010/15/schedule/3
SCHEDULE 3 Services and public functions: exceptions
Gender reassignment
28(1)A person does not contravene section 29, so far as relating to gender reassignment discrimination, only because of anything done in relation to a matter within sub-paragraph (2) if the conduct in question is a proportionate means of achieving a legitimate aim.
(2)The matters are—
(a)the provision of separate services for persons of each sex;
(b)the provision of separate services differently for persons of each sex;
(c)the provision of a service only to persons of one sex.
This is section 29 that is referred to (I won't copy it here as it is quite long, but is about providing services to people): www.legislation.gov.uk/ukpga/2010/15/section/29
aren't you discriminating on the basis of sex in one of the situations where it's legal to 'lift the veil' and not treat somebody as their acquired sex?
If someone has changed their legal sex by obtaining a GRC, their sex is their acquired sex for all purposes under the law. The exemption means that if it is "a proportionate means of achieving a legitimate aim" a transwoman with a GRC can be treated differently from a woman. A transwoman with a GRC is legally a woman, so the discrimination is not on the basis of sex, because the transwoman is no longer of the male sex in the eyes of the law. It is treating a transwoman differently from a woman because the transwoman has the protected characteristic of gender reassignment but the woman does not.
The effect is the same as not treating someone as their acquired sex.