Sweet paprika and strawberry Emperor bars, Moondance Truffles - Montezuma's chocolate shops specialise in exotic and unusual blends and flavours and take their name from an Aztec emperor who made a fatal error when he mistook invading conquistadores for gods, inadvertently introducing chocolate to Europe.

It all started, as so many grand ideas tend to do, far from home. This time, it was in a small town in Argentina, where Helen and Simon Pattinson were staying while travelling around South America for a year.

Tired of the rush and tumble of busy lives as solicitors in a big London legal firm, they had sold their house, packed up their possessions, and set off with rucksacks and a tent.

But unlike most of the best-laid life-changing plans made while idling on holiday, the sort of ideas that fade along with the suntan, the Pattinsons returned to the UK, got cracking, and within a year had opened their first shop in Brighton.

'We'd always planned to look for inspiration while we were travelling for what we could do when we went home,' says Helen, 'and we were staying in this small town, Bariloche, in the Argentinian lake district where there must have been about 10 chocolate shops, which got us thinking about how we don't really have quality chocolate shops on the high street in the UK.'

It was the germ of an idea. Unfortunately, the trip was cut short when, after seven months, Simon bent down to pick up his rucksack, slipped a disc in his back and didn't stand up again for another three months.

'We were back in England within 24 hours,' says Helen. 'I was gutted, but Simon was in agony. We had nowhere to live and no possessions apart from what we had been travelling with, so we went to stay with Simon's parents. The plan was to sort out his back and resume our travels. But it didn't work out like that as it took so much longer for him to recover.'

Instead, they began to research their chocolate-shop idea, Simon lying on the floor, researching on the internet on his laptop, and Helen travelling up to London to the British Library to read market-research reports. They needed to find out as much as they could about the chocolate industry and retailing.

'We were very naive. We never stopped to ask ourselves, "Is this going to work?", we just kept going and drew on every bit of experience we had,' says Helen. 'We had no pre-conceived ideas, but we were very keen not to copy any other brands. We wanted to create something new and exciting.'

There were no plans to make the chocolate themselves and Helen and Simon set about sourcing chocolate from small UK chocolatiers. They found premises for their first outlet, in Brighton, and everything looked like it was all coming together.

'About three months before the shop was due to open, we called the supplier who would be providing the bulk of the chocolate to tell them everything was going ahead, and were told they had gone bust,' says Helen. 'At that point, if I'd been on my own, I would have given up. But Simon had a different plan.'

They learnt to make the chocolate themselves. This meant a whole lot more to research and read about - and practise. But with help from machinery suppliers and raw-materials suppliers, they learnt to mould chocolate and turn it into bars. Keeping to the original deadline, the first branch of Montezuma's opened in Brighton in August 2000 with around 200 different products.

'The first day was pretty frantic,' says Helen. 'It was a Saturday and we didn't open until midday because we were so unprepared. But we had thought we might take about £200 and we took almost £700. We couldn't believe it. We thought we'd really have to push the product and do lots of marketing, but from the first day, it just took off. Then we were hit by Christmas and we had our parents upstairs above the shop packing truffles to help us keep up.'

Montezuma's first factory was housed in a converted stable, where Helen and Simon would make up the products in the evening after working in the shop during the day. Nowadays production takes place in a much less romantic environment in a specially adapted factory at a business park.

Their daughter, Poppy, was born in 2002, while they were living in a tiny house with no garden in Chichester. They started looking for somewhere bigger and, 18 months ago, moved into a flint-fronted Victorian villa at Pagham Harbour, near Chichester.

'We'd already seen this house and thought how lovely it was, but it wasn't for sale,' says Helen. 'Then, on the day our purchase of another house fell through, the estate agent's details for this one arrived in the post. The house was in a good state but it didn't have an ounce of comfort as it had been rented out as a holiday home. But I have a thing about symmetrical houses, I love them.'

The garden is big and rambling and Simon and Helen are now planning to convert some outbuildings that adjoin the back of the house into an inside/outside sun room and also add a conservatory. Another huge attraction of the house is its idyllic location, 100 metres from a seawater inlet, where the family often stroll and picnic.

Sharing the parenting enables both Simon and Helen to spend time with Poppy. 'It's busy, but we're lucky because we can be flexible,' says Helen. 'I sometimes pick Poppy up from nursery at about three and then do a couple of hours' work after she has gone to bed. Two very helpful grannies make a big difference too!'

Last year Montezuma's won a Green Award from Chichester District Council for its sustainable and environment-friendly stance. Instead of one big air-conditioning system for the whole factory, they set up separate systems for smaller areas that can be switched off when not needed; movement sensors automatically switch lights off when a room isn't being used; and hot water used for the non-environment-friendly chocolate-heating tanks, is recycled back into the hot-water system.

The company now employs 50 people and three further shops have opened in Chichester, Windsor and Spitalfields in London. They also supply about 500 retailers, mainly small shops, health-food stores and delis. 'We're always looking for new sites for shops,' says Helen. 'But they have to be good, right in the middle of the high street. Our aim is to bring fantastic quality chocolate to every town.'

Classic chocolate mousse, with a Montezuma's twist

6 eggs
150g Montezuma's geranium and
orange dark-chocolate Emperor bar
splash of orange liqueur

Separate the eggs. Melt the chocolate in a bain-marie. Stir in the egg yolks. Add the liqueur. Whisk the egg whites until stiff. Fold together. Chill.

Spanish fish

350g onion, roughly chopped
115g unsalted butter
1 tbs plain flour
1 large glass fruity white wine
1/2 glass water
salt and pepper
30g Montezuma's very dark chocolate (73 per cent cocoa)
12 button mushrooms
450g fresh white fish

Not for the faint-hearted, this one. A combination of fish and chocolate, Simon's own version of a mixture of different recipes. Apparently it's delicious.

Gently fry onion in a shallow pan with butter until very soft and caramelised (about 40 mins). Stir in flour, followed by wine and water. Season. Grate in the chocolate. Stir in mushrooms. Stir in fish, chopped into bitesize pieces. Cover and simmer until cooked (about 20 mins). Remove fish and keep warm in a dish. Continue to simmer the sauce for a few more minutes, adding more wine if necessary. Pour over the fish and serve with sauté potatoes.

· Montezuma, 29 East Street, Chichester, West Sussex, 01243 537385. Shops at 12 Peascod Street, Windsor; 15 Duke Street, Brighton; 29 East Street, Chichester; 51 Brushfield Street, London E1