Public Order Act 1986
(1)A person is guilty of an offence if he—
(a)uses towards another person threatening, abusive or insulting words or behaviour, or
(b)distributes or displays to another person any writing, sign or other visible representation which is threatening, abusive or insulting,
with intent to cause that person to believe that immediate unlawful violence will be used against him or another by any person, or to provoke the immediate use of unlawful violence by that person or another, or whereby that person is likely to believe that such violence will be used or it is likely that such violence will be provoked.
(2)An offence under this section may be committed in a public or a private place, except that no offence is committed where the words or behaviour are used, or the writing, sign or other visible representation is distributed or displayed, by a person inside a dwelling and the other person is also inside that or another dwelling.
(3 Now repealed)
(4)A person guilty of an offence under this section is liable on summary conviction to imprisonment for a term not exceeding 6 months or a fine not exceeding level 5 on the standard scale or both.
So, placards and peaceful protest fine.
What these muppets are up to? Not so much.
You CAN NOT just say what you like even WITHIN freedom of speech. Freedom of speech STILL requires civilised levels of respect and tolerance.
You CAN say controversial, even 'offensive' things, if there is a purpose and legitimate public interest WITHIN the law.
Thus you can question the conflict between trans rights and gay rights WITHOUT it being unlawful - the legitimate public interest is concerns that gay children and young people are having 'the gay transed away' or because lesbians feel they are being targetted and harassed to include males in their dating pools.
However holding up signs saying things like 'KILL ALL TERFS' may well fall foul of being a Public Order Offense under Section 4. This is the same thing that pro-Palestine Protesters fell foul of (with the aggravating issue of anti-semitism) when they had tshirts celebrating the Oct 7th attacks.
The LGB Alliance are 'the right side of the law' if you will. These guys, deliberately and persistently harassing the LGB exercising their democratic rights to discuss legitimate concerns (which are protected under current laws) are very much not.
But then, no one cheerleading these muppets bothers to actually have a clue what they are talking about most of the time. They just go off what they were told on social media and the latest slogan to sling at people they disagree with.