By Chris Barnett After winning the Grand National last Saturday, Willie Mullins takes aim at the Scottish National at Ayr this weekend in the hope of winning the British Trainers Championship for the first time. The Scottish Champion Hurdle also takes place on Saturday. Newbury is the venue for three important Group 3 races and the Spring Cup, run over the straight mile course. City AM Racing editor Bill Esdaile previews the best of this weekend’s racing action, with Wally Pyrah discussing Saturday’s meeting in Hong Kong. Hosted by Chris Barnett. The Punter‘The Punter’ has been City AM’s dedic…