Sounds like a fair result and in accordance with the FWS judgment:
249. It is now well-established that direct discrimination because of a protected characteristic (section 13 of the EA 2010) encompasses not only cases where the complainant affected by discrimination has the protected characteristic in question, but also where the discriminator perceives that the complainant has the characteristic, or in some other way associates the complainant with the protected characteristic. [...]
250. Applied in the context of a discrimination claim made by a trans woman (a biological male with or without a GRC), the claimant can claim sex discrimination because she is perceived as a woman and can compare her treatment with that of a person not perceived to be a woman (whether that is a biological male or a trans man perceived to be male). There is no need for her to declare her true biological sex. There is nothing disadvantageous about this approach. Neither a biological woman nor a trans woman “bring a claim of direct sex discrimination as a woman” (as the EHRC suggests). That is not how the EA 2010 operates: a person brings a claim alleging sex discrimination because of a protected characteristic of sex.
251. Take, for example, a trans woman who applies for a job as a sales representative and the sales manager thinks that she is a biological woman because of her appearance and does not offer her the job even though she performed best at interview and gives the job instead to a biological man. She would have a claim for direct discrimination because of her perceived sex and her comparator would be someone who is not perceived to be a woman. The fact that she is not a biological woman should make no difference to her claim, which would be treated in the same way as a direct discrimination claim made by a biological woman based on the sex of the complainant herself.