When Gary Robins and his colleagues set out to create Growthdeck in January 2016, they wanted to create a "hybrid" between a traditional private equity house and a dynamic online platform, which raises capital for UK companies by attracting high net worth (HNW) investors.

Three years on, Growthdeck is fully functioning and typically raises funds for firms seeking between £0.5 million and £2 million, most of which have been in business for around four or five years and are seeking to significantly increase in size very quickly. For example, many of the firms are aiming to double or triple in size within three years.

Mr...