In April 2010, however, the Milkybar Kid, as he's known in betting circles, decided to take an even bigger gamble — to sink his winnings into buying and refurbishing a substantial three-storey Victorian semi in Chiswick, with no experience of renovation and only a vague idea of what he wanted.
"I was looking for a place in Chiswick as I like the area but I never anticipated I was going to do a massive refurbishment," he says. "But when I saw this house I thought I could make something amazing with it, so I just dived in and bought it."
'Most people underestimate the importance of lighting but if it's spectacular, it can transform a house'
Though he lacked both expertise and vision, Grundy was prepared to invest time and money in finding top professionals, from an architect and an audio specialist to lighting and colour experts, to help him put it all together.
"I brought in expertise on all fronts because it was my first project, so it was hard to work out what I wanted, but I ended up with great people," he says. His main concerns were to bring more light into the house and to create a substantial double-height living space for cooking, eating, entertaining and watching TV. The space would lead out to a garden, which would also be a place for entertaining.
- © John Cullen Lighting: 020 7371 9000/johncullenlighting.co.uk
Local architect Peter Thomas de Cruz immediately understood what Grundy wanted. Using the side return to create more width and digging down into the ground to create extra height, de Cruz added skylights and full-height glazed doors to the garden, which has been designed by landscaper Charlotte Rowe.
The minimalist Boffi kitchen consists of white Zodiac worksurfaces and black stained-wood units, in which Grundy keeps his collection of cocktail shakers, vintage glasses and every kind of spirit and liqueur known to man.
He loves throwing parties — mixing gallons of his signature passionfruit martinis — and de Cruz has given him the perfect space to do it. For lighting, Grundy employed experts John Cullen, and says: "I hadn't really thought about it that much beforehand and I think most people underestimate the importance of lighting but if it's spectacular, it can transform a house."
Lucy Martin at John Cullen installed dramatic effects, from hidden spots around the skylights to an outdoor scheme which lights up the garden at night. "I wanted it to look like a Las Vegas casino," says Grundy. "I can change the lights to whatever colour I want or have them on a revolving circuit like a disco light, which is great for parties. At night this house comes to life."
© John Cullen Lighting: 020 7371 9000/johncullenlighting.co.uk
Suzanne Kingston at Interiors of Chiswick schemed the modernist Italian-inspired furnishings, including units and furniture from B&B Italia, while Hi-End installed the hi-tech audio and TV equipment.
For colour on the walls, Grundy consulted Farrow & Ball's colour guru, Joa Studholme, who devised a scheme of warm-off whites and greyish browns that reflects the minimal style while remaining sympathetic to the original features. The colours get darker upstairs, culminating in Grundy's almost pitch-black office. This is where he plays online poker several hours a day, though recently he hasn't been winning.
And you need more than luck to be a poker player says Grundy: "First and foremost you need to be good at maths. You need a really analytical brain in order to process things quickly. It can get very stressful, especially when you're losing large amounts. I've also been very lucky. There have always been times when I could have gone broke, but I didn't," he says.
Grundy started playing when he was 10. His uncle was a poker player, but Grundy only hit the jackpot seven years ago when he gambled £500 and won £40,000.
Since then he's enjoyed playing at casinos all over the world including Las Vegas, of course. But he has become a bit of a homebird since he discovered how much he enjoyed doing up his house.
"I've put all my money into this place," he says. "I've gambled that I'll be able to make more money in the future from it."
The house cost him £1.5 million and he spent another £1 million on the refurbishment. The property is now apparently worth more than £3 million. In other words, the biggest gamble of his life has already paid off.
GET THE LOOK
Interior design: interiorsofchiswick. co.uk
Garden design: charlotterowe.com
Colour consultant: Joa Studholme at farrow-ball.com