By Anna Wise, PA Business Reporter & Lawrence Matheson Housebuilding giants Barratt and Redrow have agreed to a £2.5 billion merger deal. The two firms plan to join forces to speed up the construction of much-needed homes across the country. The deal will see Barratt purchase all shares in Redrow, with plans to rename the combined business as Barratt Redrow. This values Redrow at £2.52 billion, offering a 27% premium for shareholders based on Tuesday’s closing share price. Before the merger can be finalised, it needs the green light from both sets of shareholders and the financial regulator. O…