The local Conservative Party threatened the promoter, and the venue, with action under the public order act and a vague 'other relevant legislation', but the main threat was from Israeli linked solicitors, UK Lawyers For Israel, who were threating legal action against pretty much anyone involved including the promoter, in a personal and professional capacity, and the venue. Promoter was also getting doorstepped by what she described as right wing media.
It's the SISU model really isn't it, except actually working. Doesn't matter if there's no foundation to the legal threat when one side has the money and desire to drag things out for years and the other can't afford to do that.