A clock , watch , phone displaying time is nonsense, you can set it to any time.
They should either revert to supervised tests , e.g. video , or give up.
The testing regime has so many holes, coupled with the fact that insurance companies will not take unsupervised test as proof so won't pay up, and you can't get a supervised PCR which insurance companies require if you admit to a positive LFT. This simply encourages people to not test and lie.
If a precruise test is important the £20 for a supervised test is nothing and Cunard should go back to mandatory tests day before.