I never tip. Delivery drivers, binmen, bar staff, waitiors/waitresses, hairdressers (except apprentices) are all paid at least £7.50 per hour. It's low paid but so are millions of other people who work just as hard.
I worked in the store room of a shop for years moving heavy stock, sorting stock, getting deliveries unloaded/sorted on minimum wage and no one ever tipped me for doing my job.
Why should I tip someone doing a similar amount of heavy/difficult work as I do when they're earning the same as me?
Where does it stop and how do you decide who to tip and not tip? Do you tip everyone who serves you in a shop? What about the bus/train driver, your dc's teachers and TA's, store room staff who make sure there's stock on the shop floor, carers who help take care of elderly parents, everyone stacking the shelves in the supermarket, the GP's receptionist and on and on. Most of those people will be on the same wage, sometimes less, than waiters, delivery drivers and hairdressers. What makes some jobs more deserving of tips than others?