Since puberty, Brenda has never had any issues with money: she's always been well cared for by the old guys she's latched onto. She provides the company and kudos, while they provide the cash. So for her to be screwed out of her own money by a bloke is both ironic and very inconvenient.
If she's to survive in London, she needs a job. But Brenda has issues with nine-to-five, preferring the ninety-five-and-loaded approach to income. Teaching others the art of relieving rich old gents of their spare change is one that's born out of desperation.
Craving security, as only a child of larcenous parents can, Brenda hopes to hell her school for girls pans out. Apart from the financial implications, she doesn't much fancy a love life that's destined to be littered with dodgy prostates and emergency CPR.
Of course, Julian is someone and something Brenda could not possibly have anticipated.