Yeah you might be right, only bigger shareholders are listed.

That's accounting speak for true ownership. But they do get around this listing some legal entity in a tax haven.

Yes. However, you need to hunt a bit by going into the "returns." Go into "Filing history" then tick "Confirmation statements / Annual returns." Then skip any "confirmation statements" that have "no updates." Eventually you will reach an "Annual return" with "full list of shareholders." This document will include all shareholders and is true for any Ltd company I've looked up in recent years. They just don't republish it every year.

Of course, this list may well just be other companies that are overseas and you can't drill down into their owners.. ;-)