Pretty sure that you need a licence to cash in scrap nowadays.
Correct.
You need a separate license for each local authority, and for each person involved in the collection of scrap metal, so my Aunt May and her two sons, (who have been collecting scrap for over 50 years) need 36 separate licenses between them. These all have to be displayed on the van windscreen. (Which makes it impossible to actually see out)
Amazingly, the scrap metal thieves who these measures were ostensibly aimed at, don't seem to worry about the fact that they should have a license.