We do not know what proportion of the contract liabilities has...

We do not know what proportion of the contract liabilities has been paid (and included in the last half operating cash flow) with the costs still to come.

Contract liability: An entity’s obligation to transfer goods or services to a customer for which the entity has received consideration (or the amount is due) from the customer.

They will always have contract assets for work in progress. What we do not know is why contract liabilities have suddenly leapt. It may not be of concern, but I would prefer to know a bit more about them and the potential impact on current half year cash flow.

We will get a better idea with the full year accounts.