"We figured that most of the cost was paying the operator to press `print', so we asked if we could operate the computer and save that expense," says Ms Clare, a former finance specialist with Apple Computer.
Told that customers were not allowed on the machines, they reflected that there must be many people in a similar position to them in knowing how to do the work but needing access to the expensive equipment required for short periods and at a reasonable cost.
The plan was to set up a centre where customers could walk in off the street and start working at a computer - confident that expert help was on hand if they got into difficulties.
But before they went ahead, the pair - who had met at the Insead business school in France - did market research. They sent questionnaires to a group of Kensington residents selected from the phone book and received 40 per cent back, most with positive comments.
So they put their savings into the project and set about getting a bank loan to make up the difference. After weeks of frustration they found a NatWest manager who believed in the idea but, more importantly, adds Ms Clare, believed in them. "Most banks were reluctant because it was new territory."
However, they were still not prepared for how long it would take them to be actually up and running. Having found premises and arranged the lease, they then had a problem over the name they chose - the Government objected to The Home Office. So they resorted to "declare" - taken from parts of their names.
Within 12 months of starting out, in London's Earls Court, they had outgrown the premises. And in the past six months they have bought out a competitor in Covent Garden and opened another centre in Camden Town.
Three years after setting up they have 10 employees and are looking at achieving a turnover of pounds 500,000 in this financial year. With more than 50 computers, 15 printers and six scanners, "declare" claims to be the largest do-it-yourself computer studio operation in Europe.
It has been, admits Mr de Rozairo, "a tough learning curve". But he points out that the business has helped more than 40,000 individuals and firms in its short life, and the duo's greatest satisfaction comes from watching start-up companies - many of whom are given advice based on their own experiences.
Now preparing another business plan with the aim of obtaining further funding for the months ahead, Mr de Rozairo and Ms Clare will be on hand at the Carlton Enterprise Fair, which takes place at the New Connaught Rooms in Covent Garden this Friday and Saturday.
The event - which the television company says is part of its "commitment to putting something back into the region" - will feature contributions from a range of advisers with the idea of helping anybody planning to start or already running a small business. It comes as accountancy firm Clark Whitehill is preparing a similar event for owner-managed businesses for 31 January, with speakers including shadow Chancellor Gordon Brown.
In order to promote the Carlton event, which comes as many leading banks are renewing efforts to inform would-be entrepreneurs of the help available to them, the television company is screening several short films in which Karen Jones, co-founder of the Cafe Rouge chain of restaurants, fashion designer Bruce Oldfield, and Nicola Foulston, chief executive of the Brands Hatch motor racing circuit, talk about their early days in business and what has motivated them.
Ms Jones says: "I think strong business partnership is crucial. I have learned to listen to good advice in all my plans."
It is a view echoed by Mr Oldfield, who says: "When I started, I knew how to be a fashion designer. But I had to learn how to run a business. I survived because I took some sensible advice."