A subsidiary of Oakmount, a property company controlled by the McKillen family, is preparing to go to the High Court on Monday to try and discover more about an action being taken against Dublin City Council (DCC) by rival developer Ronan Group Real Estate (RGRE).  The move marks a significant escalation in a row that centres on the development of an iconic 8.91-acre area known as the Pigeon House lands on the Poolbeg peninsula in south Dublin. DCC had named Oakmount as the preferred bidder to develop this site in May before it suddenly killed the entire project on September…