You keep saying the same thing over and over again. The point wasn’t argued, so Swift didn’t have to decide it. Fine. But if the arrangement were evidently and automatically unlawful, it would still be striking for him not to mention that while hypothesising this exact scenario.
And you keep on ignoring the point that it would not be even vaguely striking for him not to mention it because it was not argued. It would have been striking if he had mentioned it and would have given GLP an easy route to getting an appeal.
If Swift had wanted to decide that the arrangement was unlawful because of the signage, he would have needed to give the parties a fair opportunity to address it. But there was no rule requiring him to ignore or remain silent about an obvious legal defect unless and until somebody pleaded it.
Yes, there absolutely is a rule requiring a judge to ignore a legal defect that has not been pleaded. Judges are strictly bound by the boundaries of formal pleadings. However, it is not an absolute rule. Yes, he could have decided to delay the judgment to give the parties an opportunity to address it, but why would he do that? He did not need to address the legal defect to answer the question being asked.
And if the supposed illegality were really as obvious and automatic as you say it is, then yes, it is odd that Swift did not even acknowledge it while expressly hypothesising that exact arrangement, even though it was not an issue he was deciding.
He did not hypothesise the arrangement. This is exactly the point that was being put to him. EHRC's guidance states that allowing trans identifying males into the female toilets meant that any man had to be admitted or they would have a claim for discrimination. GLP said this was wrong. So the parties came up with the scenario, not Swift.
Saying “I’ve already proved it” and “you’d lose before a judge” is not a substitute for identifying the law that actually says what you claim it says.
A lot of UK law is not written down as legislation. It is trite law that any single sex facility must be appropriately labelled. The Building Regulations (which I did identify) set that out for new builds and alterations to existing properties, but it would be true even if they were silent on the matter. Following FWS, a label that says a single sex facility is for women is clearly referring to biological women. That is also implicit in EHRC's guidance which, whilst not law itself, is something courts and tribunals are required to take into account and will generally treat as authoritative.