Student unions have always been an absurdity by very definition. Unions are organisations set up to ostensibly at least, protect employees but since last time I checked students are not employees they are essentially engaged in a fraud and imposture and should not therfor be recognised by any university that relies in part on taxation.
Such a move would instantly de fang the toxic culture generated by the usually middle class playing- at working class phonies- of radicalism that make up the student 'union' leaders. The nonsense of no platforming,trigger warnings,micro aggression and the whole absurd politically correct nomenclature of grievance anti free speech culture would be terminated at a stroke.
Failing the above simple sollution and cure to the cancer, corruption and anti intellectual/ free speech culture of our state funded universities they should be put on warning that said funding will cease and they will be on their own,effectively privatised. They will then be at liberty to close down all free enquiry and see their profits freeze and face eventual closure as no parent in their right mind would pay to have their offspring brainwashed and lobotimised in a free market system of education where they could choose from a wide variety of universities and avoid the latter like the plague.