By Wally Pyrah HAPPY Valley in Hong Kong hosts its regular midweek-programme today with nine races, featuring the Class Three Hok Yuen Handicap (2.15pm) over the extended mile. The city track has continued to prove a tough place to find winners for the serious bettors recently, with just three winning favourites from the last 35 races. Champion jockey Zac Purton had to come to the rescue aboard heavily supported Chill Chibi in the last race a week ago to avoid another whitewash for favourite backers. Maybe with the action taking place on the ‘B’ track which, favouring gallopers with low draw n…