By Wally Pyrah THERE will be plenty of interest in how expensive purchase Unbelievable performs when making his first appearance in Hong Kong in the Red Packet Handicap (8.40am) over a mile. The Frankie Lor-trained colt has a pedigree to die for, being a son of American champion Justify and out of a dam sired by Galileo. The striking chestnut galloper was saddled by Aidan O’Brien last year, when known as Bertinelli, and won the competitive 10-furlong London Gold Cup at Newbury, before then finishing a close-up third in the King George V Handicap over 12 furlongs at Royal Ascot in June. After c…