May I ask Smiledwiththerisingsun what the middle ground looks like for you?
Going by your opening post, my immediate thoughts turn to the fact that across the UK there are now girls self-excluding from PE so that they don't have to change with male pupils, there are girls missing school on days when they are menstruating because all of their toilets are now mixed-sex. Our safeguarding lessons are sabotaged because we no longer allow girls to assert boundaries around their own bodies against all male children. Girls brave enough to voice their discomfort at being asked to share sanitary facilities or changing rooms with male peers who identify as trans increasingly hear this discomfort framed as problematic, disrespectful, even hateful and bigoted. And rarely is anything done to remedy their discomfort in ways that respects their rights.
The middle ground - as you call it - or as I call it the legally correct application of the Equality Act, which the Equality and Human Rights Commission published in its statutory guidance in 2014, was to make alternate arrangements for children who identify as trans. This was to make sure that they would not be discriminated against by being excluded from spaces provided for their own sex nor forced to use them, either of which could lead to bullying, harassment or worse. As the guidance spelled out in clear terms, an alternate solution did not mean inclusion of those children in opposite-sex spaces, because this would breach the rights of opposite-sex pupils to their own single-sex spaces.
Article 39 of the UN Convention on the Rights of the Child places an obligation on state actors to support children who have suffered abuse, including sexual abuse, and to enable them to recover from such abuse. If those lovely "trans or non binary kids" you know include male children who now use opposite sex spaces, what options does the girl have who has been sexually abused? Must she disclose her abuse to gain a single-sex space? What of the repercussions to her? Must she hide her discomfort, as she hides her abuse? Must she accept having her boundaries violated at school, as they are violated by her abuser? Does she grow up knowing that she is allowed any boundaries around her own body?
Keeping single-sex spaces single sex places no burden on such a child, but allows her a space to feel safe. Where she learns boundaries, that she is allowed to have them. That they must be respected - because boys who intrude in these spaces will be reprimanded.
These girls exist. By the time they are 16, six in ten girls across the UK have either experienced or witnessed sexual harassment and assault at school. Add to that sexual harassment and assault outside of school and you are looking at the vast majority. What middle ground will you find for them?
I am truly interesting in understanding your reasoning on this, because I do think it is important, if we seek compromise, to understand where we are right now - is this situation we are in right now already a violation of a previous compromise? Where did both parties start out? Is this new compromise asking the same of both parties? Who stands to lose more? Who benefits? Who doesn't?