and the second half would be good for all schools, but heads are running scared from governors, governments, Ofsted, papers, parents, pupils and legal action etc.
I think the problem is one of process.
If you're an HR director, and you get threatened with an ET, your initial response is to laugh. Assuming you're running a competent ship where your record keeping and process are basically sound, and you're reasonably confident of your ground, you do nothing until the employee actually brings the action (most don't). You then show up at the tribunal, which is more than the complainant probably will, make your case, and if it looks like the complainant has something on you, you use a compromise agreement to make the whole thing go away. You don't need to trouble the CEO, in anything other than the broadest terms, unless you're getting involved in some scary discrimination case or there's otherwise an exceptional circumstance. And as fighting ETs is more interesting than checking expenses claims, your typical HR director around town is quite happy to get involved in them.
But if you're a school headteacher, and you get a letter written on the back of an old betting slip in which someone claims to have once met someone who walked dogs for someone who used to do the cleaning for a legal secretary, you're probably going to have to inform your governors, your LEA/trust and Uncle Tom Cobley and all. So unlike in a business, where a stroppy employee can't cause any serious trouble until they're actually stood in the ET and looking like they're winning, in schools they can make the head's life a misery just by making the vaguest threat. So the head will do anything they can to prevent them even getting to the stage of vaguely threatening an action. So for a head, losing a couple of grand at a hearing, or even winning at a hearing, is such a major thing that it's worth spending huge amounts of time and money to avoid it happening. Court and tribunal cases acquire a disproportionate power, because the value assigned to them is unrealistically high.
The solution would be to give heads the power to settle small cases, and a clear understanding that losing court cases is, within reason, a risk worth taking. If heads' response to a threat of a tribunal/court action was "Go ahead, make my day", matters would be rather different.