There's plenty of tradesman on here. I'm sure they will have at some point, turned away jobs because they weren't worth there while. If I was a cabby i'd probably not be inclined to run you that short way for a £5 fare and then have to spend the next half hour queuing before I got another fare...
A large majority of black cabs have CCTV these days. Actual proof for the benefit of driver and passengers. It's all well and good having all the information of an Uber driver but if the allegation boils down to one word against another, it doesn't help.