There's no deadline as I see it. The Xinwen board has approved...

There's no deadline as I see it. The Xinwen board has approved the purchase, but Linc has accepted an extension of the 'heads of agreement' until the Chinese government regulators give their consent for Xinwen to sign off on the contract. Linc in their latest announcement gave no time limit to the extension period.

The previous announcement mentioned a period of 30 days due diligence (from about 6th of September), Execution of the sale and purchase document by 05 Oct, then immediate payment of the first tranche upon federal and state government approvals (expected to be 45 days from 06 Sept). There was no mention of approvals being required by Chinese government authorities. It wouldn't have been unreasonable for Linc to assume that Xinwen and the Chinese government are a single voice.

So anyway, the first announcement was quite specific - deal between Xinwen to be formalised 06 Oct, Australian government approvals approx 45 days (from 06 Sept, so that would be approx 21 Oct) then immediate first payment.
Linc's gone from that to no specificity as to the Chinese government's approval date.

This is just my thought, but if the Chinese government can see some weakness to exploit in Linc's position it'll use it. I'll only believe the deal's done when the first tranche of $150m is in Linc's bank account.