Seems the price jump leading to the ex-div date 01/03 was mostly due to the fully franked special distribution
Price was pushed to $5.3 at one stage, after the ex-date, it dropped and settled around $4.5
The value of FF distribution = $0.35 (div) + $0.15(FF) = $0.5 though
Would have been a good arbitrage if someone sold back in Feb and buy the share back now...