well found a guide on another forum with some slightly overcomplicated instructions regarding an adjusting screw at the pedal and stuff. but in there it said to wind the shoe adjusters up until the disk locked and then back off 6 "clicks". I figured since the cable and shoes hadnt been touched i could probably leave that and just tweak up the shoe adjusters.
So i whipped the wheels off and tried doing just that, and now the footbrake feels much better. gets nice and heavy at about 6 clicks and car struggles to drive forwards with it on that much now.
Just need a retest now.
Annoyingly, because it had COVID-Extension, and has now failed a test, the MOT is immediately void, rather than running until the end of september, so i now cant use it at all until the retest.