They have not increased the profit estimate for the full year...

They have not increased the profit estimate for the full year but just the split between first and second halves. The explanation would be that they are recognising margin in the first half from the Ichythys SMP project that must have been at least 30% complete at 31Dec.
It is still positive, so surprised to see 550k go through the market without a decent price rise - maybe the seller knows that they won't be declaring a dividend for the half year which would have certainly boosted the share price.