They broke into an RAF base, and defaced/damaged UK military hardware (spraypaint on aircraft). This is a serious crime, but in no way does it meet any reasonable definition of terrorism. There are plenty of laws under which those responsible can be charged, it was a ridiculous overreach to use anti-terror laws.

More concerningly, prescribing Palestine Action as a terrorist organisation had a suppressive effect on lawful protest against the Israel-Gaza war, since any supporter of Palestine might be considered a member of Palestine Action and therefore, legally, a terrorist suspect.