By Amber Murray Online grocer Ocado, which had a difficult start to week after shares plummeted when a leading broker downgraded the stock, has reported a pre-tax loss of £153.9m for the first half of the year. The company told markets this morning, that it had revenue of £1.5bn, up by 12.6 per cent year on year, driven by 22 per cent growth in technology solutions. Ocado has shifted its focus in the last few years to providing B2B robotics and automation services, with some suggesting it could spin out the retail business to focus solely on tech. The group reported earnings before interest, t…