they make up the bulk of delivery cyclists

And car washers, couriers, anything that could basically be a zero hour contract job that only has something to do immediately after a customer places some kind of order. So it's a lot of sitting about doing nothing then eventually getting some kind of order that can be done and paid in cash, because the businesses involved are also avoiding a lot of tax procedures in the same way these "workers" are flat out not paying any tax on their "wages".