"My name has been awkward for two reasons, there was a famous interior designer who did the work in Buckingham Palace ... and obviously in Australia for another reason, but I think it's passed."

National security jokes aside, Hicks has made a name for himself building the dream homes for Melbourne's wealthiest families and businesspeople.

From home cinemas to hair salons, burglary-proof jewellery "wardrobes" to plush panic rooms, Hicks has seen – and conceived of – it all.

"For our clients it's all about not settling for second best ... no matter what the cost," he says.

But it's not only about money, even for the most moneyed people in town, Hicks says.

"What can be baffling sometimes is the amount of money people may spend on a certain thing that they love – that can sometimes blow your head off. Most of the time it's about being classic and timeless. We try not to pick things because of their cost but because of the longevity, the luxury," he says.

Still, some of the costs are pretty mind blowing. An €100,000 ($147,000) sofa or a €180,000 ($265,000) antique French mirror.

Interior designer David Hicks with his 12-week-old puppy, Jett. He has worked with clients who have spent in excess of $250,000 on a single piece of furniture. Photo: Getty Images

So is there room in these people's homes for the odd IKEA piece? Hicks' answer is a firm "no".

"The lifestyles our clients lead can sometimes be a different reality. I have designed walk-in robes customised around shoe collections of 300 pairs and Birkin bags in every colour – it's truly another world."

When Melbourne's wealthiest families and celebrities need a florist, a caterer or a personal shopper, they don't ask Google. Instead, they tap into an exclusive network of providers, six of whom have agreed to speak to Fairfax Media on strict condition their clients' privacy is protected.

You won't find their faces plastered across social media, nor do they advertise. But in certain circles, they are almost as famous as they people they service.

'You won't find my work on Instagram'

Outspoken florist Fleur McHarg is on the speed-dial of Oscar winners and top fashion houses, and has had the contracts for state dinners and numerous official functions.

After 20 years in the industry, her relationship with many top clients has progressed to friendship.

Everyone in the Melbourne club said discretion, attention to detail and a knack for the special touch has helped them attract prestigious clients. Photo: Simon Schluter

Despite smoking in their company and calling everyone "Pet", McHarg won't be drawn on the identities of her most dedicated clients.

"I have close to 50,000 followers on Instagram and I've never posted a photo of a VIP job. No one would ever know. That's the way it's meant to be and that's why my clients are my clients," she says.

Still, there are some stories she can share, including being commissioned to fill Barbra Streisand's toilet bowl with gardenias while on tour – a fact that has been written in numerous biographies.

Or the time she created sugar-coated baubles for a prominent family's Christmas tree, only to have them invaded by an army of ants.

And the time she was forced to make small talk with royalty and ran late for a meeting with an international client.

"One rule is you never let one client know who the next client is because you never want them to think the next person is more important than them," she says.

'Celebrities are still people'

When dealing with people who have millions, or billions, charter plane VIP manager Donna Linton, of Southern Cross Jets, says it's important not to become star-struck.

"No matter how wealthy or famous they are, they are still people," she says.

And even celebrities need rest. For Linton, sometimes that means waiting on the tarmac for hours until an entertainer wakes up.

Private jet guest relations and cabin crew manager Donna Linton gets to travel around the world with her high-profile clients. Photo: Simon Schluter

"You get to see into people's private lives as their staff at home do. You're literally putting them to bed," she says.

Still, there are plenty of "pinch me" moments, from travelling to exotic locations in Africa or the Middle East, or serving Champagne on board while juggling a client's puppy.

Despite some gentle prodding, she won't say who the client was ... but it wasn't actor Johnny Depp.

'You have to be ready for anything'

Some celebrities have a reputation for diva-like behaviour and making unreasonable demands. But just as many look after their bodies and work really hard, insists caterer Liz Long and trainer and nutritionist Wendy La Roche.

Long has catered for stars including Lady Gaga – "a lovely person who was really interested in the food" – and says many celebrities want superfoods: "Lots of kale, seeds, lots of green".

For the Melbourne Cup she's staging "the full catastrophe" for one of Melbourne's wealthiest families at Flemington, across six car spaces for 110 people.

Caterer Liz Long prepares food for many celebrities, including on their private jets. She says flexibility is the key to success at the high end. Photo: Simon Schluter

She says the secret to working with the rich and famous is "keeping everything fluid and open – you have to be ready for anything".

For La Roche, who owns a gym with her husband, that can mean helping a starlet shed five kilograms in a matter of days for an awards show or live performance.

"They normally have a perception that we need to starve to lose weight and I don't know how to do that. They need to eat as you drop weight or else they will be 'skinny fat' and I tell them they don't want to look that way," she says.

Trainer and nutritionist Wendy La Roche often has only a few days to get a celebrity into shape for an important performance. Photo: Simon Schluter

'We're not slaves to fashion'

The need to look a certain way has kept Suzy Crittenden in business for 15 years, with clients including the wives of a premier and a governor, lawyers, doctors and the odd society mistress.

"I don't think I could confidently dress anyone younger than 45 ... It's a different look ... there's a lot of lurex now and it's just not right for [my clients]. I am very confident with my age group – we touch on fashion but we're not slaves to fashion."

With her clients spending anywhere between $5000 and $30,000 a season, she makes it her business to know what's coming in, who's bought it and where they're planning to wear it.

"These women cannot afford to go to a cocktail party and stand next to someone wearing the same dress," she says.

Personal shopper and stylist Suzy Crittenden stays on top of collections to ensure no two clients are wearing the same outfit to an event. Photo: Simon Schluter

Crittenden has about 20 clients on her books who call her twice a year for a wardrobe update.

Once, she dressed the wife and mistress of the same man for the Spring Carnival, with neither woman the wiser.

And that's the point. For these six members of the "Melbourne club", discretion, details and trust are their currency. In return, most of their clients give them free reign.

As McHarg puts it: "They ring me direct because they know it's going to get done ... If they want to snap their fingers there aren't many people who will do the best job for them. I don't care what they're paying, I just do it.

"They're busy people. They don't even ask to see a photo [of the flowers]. They know I am not going to screw it up."