WHEN my husband asks me to bring back a pair of galoshes, size 13, from New York, I realise he hasn’t quite got the hang of shopping sprees. But then he is a man. And that is why I have chosen to travel with a woman - my niece Heather. She is good company, and sometimes wise beyond her years. And at 19, she still qualifies for a new Manhattan-based shopping package, geared for the teenage market, the Girl’s Guide to Glamour in Gotham.

It’s organised by Shop Gotham - New York’s only specialist shopping tour company, in conjunction with the Mandarin Oriental hotel. Here is what is promised.

First, insider knowledge of where to shop in a city that is overwhelmingly retail focused. This might include a whistle-stop tour of classic shopping landmarks such as Bloomingdale’s or Barneys — though to my mind these are rather staid for the teenage market. Teenagers are, however, encouraged to make their own requests, so we opt for the quirkier boutiques of lesser-known districts such as NoLita and SoHo.

Add to the package a chic hotel room with knockout views over Manhattan’s skyscrapers, advice from a fashion stylist, as well as a makeover, manicure, pedicure, and a swanky stretch limo to whisk you from one location to another - and this special treat experience sounds improbably wonderful, not only for Heather’s age group, but for mine, too.

But here is a girl who takes things in her stride. And when filling in Shop Gotham’s prearrival questionnaire, Heather sees no need to impress. Favourite designers? “Not sure of designers, as I shop on the High Street - Topshop, Mango, H&M.” Under requests, she writes: “To develop my own sense of style and find something unique. A party dress and skinny jeans that don’t make my legs look too big - if that is possible.”

This is Heather’s first trip to New York, and on the drive from the airport I gauge her reaction. She is silent — probably exhausted by the flight - but clearly entranced by this larger-than-life city, with its neck-straining skyscrapers, car horns and hyped-up atmosphere.

Over the weekend, it is as much the minutiae of everyday Manhattan that fascinate her as the commanding buildings and clamorous streetlife. In the Flame Diner, on Columbus Avenue, she scans the room, takes in the peppermint-green booths, mouthy old ladies, Homer Simpson-sized pies topped with whipped cream, and delivers her verdict: “Per-fect!” Then, reading the menu: “Eugh, look! Bagel deluxe with smear! How revolting does that sound?”

Replete with eggs overeasy, it is off to Bergdorf Goodman, one of those glitzy Fifth Avenue stores that seem geared for the moneyed middle-aged. But up on the fifth floor there is an altogether different scene, with desirable clothes from groovy young Manhattan designers.

Domenica, our Bergdorf Goodman style consultant, is like Trinny and Susannah turned benevolent. She styles celebrity clients - stars as diverse as Goldie Hawn, Beyoncé and Julia Roberts, and she tells us of the fun she had “funking up a 40-year-old with a Chanel obsession”.

We love her suggestions - wispy silk fairy dresses teamed with cowboy boots, for example - but the prices are way too high; sadly, even the Diane Von Furstenberg wrap dress that suits my niece perfectly.

“It’s all great, but a lot of this,” whispers Heather, peering at an expensive check shirt, “is what I would call geography teacher chic.”

Downstairs in the Buff Spa, we have manicures and pedicures - the latter is a first for me, and the beautician, sensing I’m a pedicure-virgin, reaches for her arsenal of tools and drills and gets to work.

The Chanel makeover is less successful. Heather’s assessment: “too old lady”, and my eyes stream from the onslaught of mascara. But it is here that we meet up with Halle, our twentysomething Shop Gotham guide, a reassuringly studenty blonde with tweed cap worn backwards and acid green shoes.

“This tour is meant to feel like shopping with a girlfriend and we show people districts they may not know, such as NoLita or SoHo,” she tells us as we struggle to look to the manor born in our stretch limo. And Halle is ripe with teen-appeal anecdotes - for example, pointing out the Mercer Hotel, where Russell Crowe threw a telephone at the receptionist.

In the boutiques along Spring and Prince, Heather finds her ideal party dress - but at £143 including the stinger sales tax added at the till, again way beyond her budget. So, too, the Henry Lehr jeans shop - with many denims, our pocket calculator tells us, starting at a cool £90. But at the Young Designers Market in St Patrick’s Youth Centre, a venue we would never have discovered ourselves, a bargain retro dress is bagged for £25.

Halle’s tips on where to hang out also prove spot-on. She recommends not scaling the Empire State but taking cocktails in the Rockefeller Centre Rainbow Room - and we duly toast the lights of Manhattan from the 65th floor, with a glass of champagne.

At Blue Ribbon, a hip downtown restaurant on Sullivan Street, we spend a memorable evening with chatty handsome waiters telling us about moonlighting in rock bands, and tipping us off that Mariah Carey has arrived.

Essentially, it’s these moments - experiencing the New York lived by New Yorkers — that appeal to Heather. The all-American diners, the ranting cab drivers, the scruffy subway, as well as a Sunday stroll through Central Park, where she laughs at skippy dogs and diversely shaped joggers training for the marathon.

She has no desire to wander off alone. Instead we also take in touristy stuff together - Times Square, “tacky, but at least it knows it”, a whiz round MoMA that delights us both, and a walk through the pristine Byzantine halls of Grand Central Station.

And she got her party dress. Sadly, I cannot say the same for the galoshes.

Need to know

Getting there: Louise Roddon and her niece travelled with Elegant Resorts (01244 897520, www.elegant resorts.co.uk), which offers three nights’ room-only at the Mandarin Oriental New York with the Girl’s Guide to Glamour in Gotham tour from £1,725pp, based on two sharing and includes Virgin Atlantic flights and private transfers.

Further information: www.shopgotham.com. A new book, New York in Store (Thames & Hudson, £12.95), has more suggestions.

Teen treats in New York

Take a thrill ride on Shark (www.circlelinedowntown.com/shark.html), a speedboat that whizzes to the Statue of Liberty in minutes, for £9.

Helicopter flights (www.libertyhelicopters.com) over the skyscrapers or the Statue of Liberty cost about £35 for a seven-minute flight - expensive, but worth it. For younger teenagers, check out America’s oldest toy store, F.A.O. Schwarz at 767 Fifth Avenue (www.fao.com), also Niketown (Fifth Avenue at 57th), and the MoMA design store for funky school accessories.

Eat at the Jekyll & Hyde Club at 1409 Avenue of the Americas (a “haunted house” themed restaurant with thunder and lightning, and skulls that come to life). In Central Park, hire bikes from Central Park Bicycle Tours (£5 an hour, follow signs at south entrance), or, until April 8, go ice-skating in the park (www.wollmanskatingrink.com) for £4.50, lessons available. A New York City Pass (www.citypass.com), adults £27, youths (up to 17) £22, offers savings on six major attractions, including the Circle Line Cruise, the Empire State Building and the Intrepid Sea Air Space Museum.

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