He would eventually like to employ barbers directly, who would drive to clients in a van: mobile barber shops on wheels.
The prize was £10,000. To get his company up and running, he recruited a rival from the competition, a fellow student called Nana Darko, whose confident air had impressed him.
Darren promised to make Nana rich. He was similar to him, a young black man from south London with dreams of business success.
Together they pounded the streets of Brighton, signing up barbers to their new app – all barbers, not just the Afro-Caribbean ones.
There were constant problems with barbers not turning up on time at the salon. Negative customer feedback was building up. They also hadn’t figured out how to make any money from the platform.
As of this week, there are three vans in operation
The competition money had dried up and the app seemed ready to die a natural death in the app store.
Nana too was feeling bitterly disappointed. He had graduated with a first in engineering. But he was missing out at dozens of job interviews in the corporate world and he couldn’t figure out why. Was it the way he presented himself, the way he talked, or perhaps the colour of his skin?
They would focus on the side of the business that had at first seemed so implausible and try the idea of mobile barber vans – only this would allow them to control the whole customer experience.
Through family and friends they were able to raise a five-figure sum in a last-ditch attempt to jump-start the business and in the first van was ready – a Ford transit Darren customised outside his parents’ house. The back of the van was all stripped out, to turn it into a mini-barber shop, powered by an electric generator.
In 2017, Darren left Brighton and took a full-time job with a multinational company that specialises in sports betting, while trying to keep Trim-It going in his spare time
Word spread partly due to some celebrity customers such as musicians Charlie Sloth and Sneakbo, who both have hundreds of thousands of followers on Instagram and Twitter.
As Darren and Nana had intended, the kind of people making the bookings were mostly young, black millennials – people like Lewis, from West Norwood.
« If I was 15 or 16, then I’d go to a barbershop, » says Lewis. « But I’m 23, managing properties and working part-time, so I don’t have time to go to a salon and wait for my turn. »
He might miss some of the banter in a typical Afro-Caribbean salon, but if he feels like company he can invite friends into the back of the van where there is 
a small bench for them to sit on, he says.
Buoyed by the early interest, Darren was able to sign up more investors, allowing the team to raise a six-figure sum. Around the same time it was becoming clear that there was a shortage of barbers catering to Afro-Caribbean people in parts of London with large numbers of well-paid workers.
« We’re finding that because there is a bigger black middle class and there’s more people working in the City, that we have pockets of customers there, » Darren says.
The van also turned out to be attractive to a new generation of black middle-class professionals looking for a haircut while working in trendy areas such as Old Street, Bethnal Green and Shoreditch.
The increasing number of black professionals may mean that the relatively high cost of a Trim-It cut – £25 – is not an obstacle to growth. But there are others.