The prorogation in 1948 was about creating a pro-forma session of Parliament just for the purpose of passing a law an extra time, so as to pass it over the objections of the Lords. It didn't actually prevent Parliament from having its say, which is the issue today.

https://en.wikipedia.org/wiki/Prorogation_in_the_United_King...

(BoJo's government still has the confidence of Parliament until it doesn't- that's not what the court ruled on)