CONSISTENT campaigner Jacko, who ran most pleasingly at his last start, turned in a top trial on the Sha Tin equitrack for regular rider Nigel Tiley yesterday. Jacko is likely to make his last appearance for the season at the bumper Sunday finale and on this trial, he is likely to be a threat. Ivan Allan started half the field in the eight-runner trial, the last of the season, but it was Jacko who really caughtthe eye. He came home very sweetly for Tiley and went across the line together with Shaka Zulu, but without real pressure being applied from on top. Shaka Zulu was held together by John Moore and seems to have taken no harm from his last run, suggesting that he might be a candidate for glory on the last day - and a definite chance for the defending champion trainer. Shaka Zulu won two starts back on his re-appearance and caught connections slightly by surprise. He did not really back up when produced again quickly although he was knocked about coming to the home turn. But he appears to be on the right track again and this trial will have given connections confidence. Allan's useful-looking griffin Mighty Mighty, who found open company and the bustle of a Happy Valley night meeting a bit too much at his last start, ran a very handy third in the trial under Frankie F. C. Lor. Mighty Mighty went to the line under a good hold and is certainly progressing on the right lines. With any luck, his trainer should have a capable horse with which to work next season. Valiant Red was pushed out to finish fourth with the remainder just going around.