I am not a cockney but to that particular barmaid anybody who spoke with a southern accent must have been a cockney.
Went to St Andrews once and was told 'look after your car mister £2' I paid it as it was only £2, but a nearby driver told them to f..k off. he came back to find 2 wheels...
About 20 years ago I went into a pub while working at The Midland hotel and ordered a Light & Bitter and the reply given was ' f..k off we dont serve cockneys'. very friendly staff/