A long-running dispute involving the property developer Greg Kavanagh in relation to a derelict mansion called Wynnstay House on extensive grounds in Clonskeagh, Dublin 14 has begun again.  The case is the latest litigation involving Kavanagh, who was last week embroiled in an acrimonious dispute with his brother Hugh. This saw the High Court on Friday make a preliminary ruling in Greg Kavanagh’s favour when it refused to grant an injunction requiring him to give his brother Hugh 14 days’ notice of any major transactions involving the property group they once ran together.  The Wynnstay House dispute also has a…