We have in Dorset / Hampshire / Wiltshire a small chain of large swag shops, as in you name it they'll clear it . . . .
Useful for all sorts of stuff on occasion . . . . https://www.in-excess.com/ . . . . the kind of outfit where stock changes by the day.
Currently they have lots of soundproofing material . . . . coyotes' cojones, damn good stuff and a bargain.
https://www.in-excess.com/collections/car-tools-accessories/products/soundproofing-under-felt-material-carpet-lining-insulation-car-van-camper-oem
Another goodie is 3M face masks complete at less than the cost of a dec