This post, given its timing immediately after the Court of Appeal decision that the proscription of Palestine Action was lawful, appears to be open support for a proscribed terrorist organisation and could arguably be a criminal offence under section 12 (1A) of the Terrorism Act 2000, punishable upon conviction with a maximum term of 14 years imprisonment.
A direct reference to the specific organisation is not required for this offence to be committed if the context is clear. Here, you specifically cite arrests of people for ‘holding up signs’. Those signs did express support for Palestine Action. You have a history of expressing support for members of Palestine Action and their actions. Thus, your meaning and intent are obvious.
There is no exemption for ‘reasonable political disagreement’, especially given that a competent individual must be expected to know that the ‘Palestinian cause’ can be supported by protest and civil disobedience without any reference to the group Palestine Action.
You should consider issuing a statement clarifying that whilst you fully endorse the right to lawful protest, you do not support terrorism or Palestine Action. I appreciate you might find this tricky given your party’s support for the jihadi Islamofascist terrorists of Hamas.
(1A) A person commits an offence if the person—
(a) expresses an opinion or belief that is supportive of a proscribed organisation, and
(b) in doing so is reckless as to whether a person to whom the expression is directed will be encouraged to support a proscribed organisation.