As Gina Miller showed quite clearly in 2019, it is quite possible for even a member of the public to hold the government to account, and to take them to court for their electoral actions

It has been, yes. Which is no doubt part of the reason the Conservative election Manifesto for 2019 said

We will ensure that
judicial review is available to protect
the rights of the individuals against an
overbearing state, while ensuring that
it is not abused to conduct politics by
another means or to create needless
delays. In our first year we will set
up a Constitution, Democracy &
Rights Commission that will examine
these issues in depth, and come
up with proposals to restore trust
in our institutions and in how our
democracy operates.


Which of course immediately raises the question who gets to decide if an action like Gina's is fair or abusing the courts] to conduct politics by another means or to create needless delays.