The penthouse floor of Glandore has a balcony that curls around Fitzwilliam Hall, a scenic Georgian-inspired building with views along the Grand Canal. Cathal Friel’s office takes up just one half of the floor, but it is the home of a series of companies he has listed on the stock market. From this building, and in his old office less than fifty yards down the street, Friel has helped create $3.5 billion (€3.2 billion) in value for investors from a series of listings. The roll-call of IPOs goes back more than 14 years to exploration company Cove Energy, which he helped…