I just went and paid for work on my bus by instant bank transfer, no need to carry the cash around, set up a payment by getting their bank account sort code and number then pay them via mobile when you get there, then you don't have to carry cash, of course it only works if you both bank online...
Woody, the ad says he's in SE19, Thats where I live, so if you want me to do anything, Pick it up or anything, give me a shout