Someone is most likely choosing to sell in 4,000 and 4,500 share...

Someone is most likely choosing to sell in 4,000 and 4,500 share parcels. If you look at the Waratah capital trades summary in their recent increased shareholder notice they have been the buyer of heaps of these 4,000 and 4,500 share sales. I'm not sure these trades are being controlled by the same two parties as you suggest. I do however agree it looks that way from the screen shot you provide.

Below was one tiny piece of the Waratah trades that made up their increased shareholder notice. Without counting up all 58pages, there would be well over 100 trades of 4,000 shares or 4,500 shares where Waratah capital was the buyer. I can't tell from this whether Waratah capital kept on putting up 4,000 share bids or someone kept selling 4,000 share parcels into their larger bid. The end result was them buying a heap in smaller 4,000 parcels.