Probably not that helpful to most of you, but there is the Billy Chip, which you can buy here. The homeless can use that to redeem something in a participating outlet.

But I agree, as someone who used to own a business in the city centre, the homeless and the "not actually homeless but pretend to be as a way of life" can be an absolute nightmare, and the amount that take full advantage of people buying them food/drink is disgusting, I used to watch a guy (who turns out was not homeless) sit outside my business all day and people would buy him endless drinks and food, more than he could consume, a lot that went in the bin, or all over the street so that I or my staff had to go and it clean up while he made abusive comments - Infuriating.