By Laura McGuire Britain’s mega-wealthy have been ramping up investment in commercial and residential properties, as they look to cash in on the uncertainty in the market according to a new report. According to a new study byInvestec, shared exclusively with City A.M., some 77 per cent of corporate executives, and financial hotshots making more than £510k a year have been looking to increase their exposure to UK property investment. Respondents said on average they will invest an additional £380k. Around one in ten said they are planning to increase their exposure to the sector by £500k or mor…