The group of 30 young consultants, the youngest being six and the oldest 16, have gone on meeting every month to suggest more ways of making the theatre an even friendlier place.
The results are impressive. The light and airy corridor to the theatre is lined with boards of drawings the children are invited to make after every performance. Overhead swing mermaids, seahorses and sea-wrack, made by the Edinburgh Puppetry Laboratory, because the children thought the descending passageway "led under the sea".
They asked for, and got, a room of their own with a couple of PlayStations, controlled access to the Internet, books and games. It is unsupervised and the children enter with a swipe-card.
They get free tickets for the films and plays they read about in the zingy house magazine Wow.
They would have read about Tall Stories, the specialist children's theatre company (last here with The Gruffalo) that is touring schools and theatres in central Scotland this week, who were giving two Sunday performances of Mum and the Monster. The trick of the preview is to say enough but not too much. Wow promises six-year-olds and upwards a play about a small boy who tries to save his mum from a monster - formulaic and cliche-ridden, I hear you cry - but then qualifies it with "where nothing is what it seems to be".
The rider is crucial, because this ostensibly simple story of country folk, strewn with stories of giants and witches, told in the language of the fairy tale, is really no less than a devastating close-up of a family break-up.
The shocking moment comes when we, the audience, willingly colluding with the folk tale narrative, suddenly find our time of innocence ended as abruptly as young Tom's, who finds in one night that giants are merely tall men, witches merely old women and monsters only men who replace your father in your mother's affections.
To explain the delicacy, wit and theatricality of Tall Stories' story-telling would be to dissect the butterfly, because the three players delicately flick through the action with the lightest of touches, in a perpetual fountain of ingenuity and imagination. If Patrick Bridgeman (Dad), Lesley Cook (Tom) and Sarah Goddard (Mum) fit the story like a glove, it is because they devised the performance from an idea by Toby Mitchell, who then wrote the script. Each of the three plays an instrument - accordion, violin and clarinet respectively - and their playing and singing is in turn mood music, sound effect and story.
It all adds up to a captivating story that turns on a sixpence to reveal one of the major traumas a child can endure and does so by manipulating the conventions of children's theatre so that we experience it as a child might, without the psychological and sociological baggage we gather as adults, or such adult emotions as jealousy, anger or guilt.
These resonate in the mind afterwards and, because Tall Stories prepared this production in workshops with school children, no doubt the mums and two dads in the audience and the teachers would have had to field questions in the following days. But that's how theatre should work on people: slowly, from the inside.
Tall Stories, tel 020 8343 8527www.tallstories.org.uk