Try Wilko they have a nut and blot sectionThat may indeed be very awesomely helpful -assuming your nuts ain’t as rusty as mine !
It’s the bolt and ‘captive’ square nut which secure the EAS Driver to the plastic filter housing.
I’ll pload a pic when I get home tonight.
jut don’t go to any trouble, I’ll have a poke around in Screwfix and any decent iron monger I can find !