I studied in London for two years out of by three year BA program (2018-2020), and due to COVID had to move back to Estonia to complete the last year remotely. Recently I visited London again to catch up with old friends and was really bamboozled by these "candy shops", they all had the distinct air of suspiciousness around them.
I've never really liked Oxford Street however, even before the flood of US candy. Shopping malls are much better than high streets for actually buying things imho.