The organisers promise a day of fun and confidence-building. "It won't necessarily lead to modelling," says Sharon Obee, co-director of the agency, "but your child will be introduced to behind-the-scenes and by the end of the day, they will be confident on the catwalk."
Marlon has heard of "that Moss person", but thankfully doesn't complain that it's a really girly thing to do. This is fortunate because when we arrive at the Islington studio, there are 20 girls waiting and just three other boys. Marlon plonks himself on the catwalk with a look of glum resignation. What his mother makes him do in the name of work.
Mothers (there is no father in sight), sisters, aunts and grandmothers, multi-ethnic but all equally anxious for their potential supermodel miniatures to succeed - are banished from the studio. The last thing an emergent supermodel needs at this stage is a pushy relative in tow. I am allowed to stay behind by special arrangement.
Sharon does the introductions. There's a girl from the Philippines, another from Barbados, lots of Hayleys and Joannes and Natalie, who is six. This is meant to be a workshop for seven to 11 year olds. "There's always someone who sneaks in," says Sharon.
Wayne, 6ft 2in at least, is the choreographer. To the Clothes Show theme tune, they pace the catwalk one by one. Little Natalie has obviously done this before. She is all swinging hips, smiles and brilliant timing.
Some look down, or turn awkwardly. The little girl from the Philippines simply looks petrified. Marlon seems uncomfortable. "Look out of the window," insists Wayne, who is trying to change Marlon's posture. Somehow I can't resist shouting "smile" at him and he glowers back. "The girls need to swing, the boys need to be more cool," says Wayne by way of conclusion.
Louise has come along to show them how to use make-up. The girls get flowers or sparkle on their faces while the boys are given fake scars and gashes. I am dying for a girl to demand a ghastly wound, but they disappoint me.
Over lunch, a 10-year-old tells me she wants to be a model because it's sexy. Kayley (striped top, mini-skirt with sunglasses tucked in the back) bounces down the catwalk and tells me her secret. "I go to dance and drama classes already," she says, "which helps with my posture." In the afternoon, Wayne is back for the grand finale, when all the mothers and co turn up to see the transformation of their wonderkids.
Everyone has brought clothes to change into. Marlon is insisting on wearing his bright orange and blue M&S swimming shorts with a bright red Billy Bragg T-shirt. I'm trying desperately to convince him the supercool black young Elvis T-shirt is a far superior choice, but he ignores me.
By the end of the day, they've practised their turns, swirls and assertive model walks to exhaustion. The time has come to let in the eager relatives. The girls and boys hit the catwalk in their motley clothes combinations. One plump girl still walks like a builder after a few beers and Natalie is still the star, but at least they all have a go. Even Marlon tries to impress his pushy mother.
What was his favourite part - the clothes, perhaps? The hair? The make-up? "Putting away the catwalk boxes afterwards," says Marlon.