Following my article on Tuesday about the Government failing to hold emergency talks with UK-based chemicals manufacturers on ending the shortage of ingredients for Covid-19 tests - the vital reagents - I have uncovered another troubling potential roadblock to increasing the volume of tests.
It is all quite complicated, so please bear with me.
What I have learned is that just under two weeks ago, the Government paid several million pounds to purchase two million "rapid lateral flow diagnostic test" kits from China - with one million coming from a company called Wondfo and one million from AllTest.
Both of these tests have EU approval for use by medical practitioners.
They can be deployed and used in hospitals in the UK right now.
Of these tests kits, one million - the ones made by Wondfo, which also have Chinese FDA approval - are scheduled to arrive in the UK in the coming week.
At another juncture I will explain why the AllTest ones are being held up - it is a slightly sorry saga.
Just to be clear, the Government has handed over millions of pounds in cash for these tests.
Which presumably means ministers and officials think they work - because as the Prime Minister's spokesperson said on Wednesday: "We only buy tests which work."
And for the avoidance of doubt, there is plenty of evidence they work - not least that they were deployed at the epicentre of the crisis as it started, in Wuhan, to assess who was infected.
Which takes me to my first big point.
Tests like these - blood tests, which involve a pin prick in the thumb so that blood can be transferred to a testing strip - have been described by the government's chief medical officer, Professor Chris Whitty, and the chief scientific adviser as being useful to identify who has had the virus and is therefore likely to have acquired immunity.
They are serological tests (testing for antibodies in the blood which indicate immunity) that would give individuals confidence they can re-enter communal life without the risk of either getting sick from coronavirus or spreading the virus.
But - and this really matters - the manufacturers are absolutely clear that their tests identify two kinds of antibody, IgG and IgM in whole blood, serum and plasma.
This means they can be used to identify whether someone who has symptoms actually has the virus.
They would therefore be a cheap, efficient alternative to the laboratory tests that the government is struggling to scale-up to the promised 25,000 a day - current capacity is a bit under 13,000 a day.
Why does this matter so much?
Well it means that in theory within the next few days a million testing kits could be distributed to the UK's hospitals to give a very rapid test - literally within minutes - of whether frontline medical staff either have Covid-19 or have had Covid-19.
Which in turn would be seriously useful in making sure that the number of doctors, nurses and other hospital staff available to treat the seriously ill isn't seriously depleted by the current system of quarantining anyone who lives with someone showing symptoms.
This takes me to my second big point.
Public Health England (PHE) has had the opportunity to assess whether these tests work for the best part of a fortnight.
And for reasons that are extremely unclear, it has not expedited that assessment.
In fact I have been given reports of PHE officials being startlingly negative about the usefulness of these tests, even though the Government owns them and they have not been vetted here.
As I mentioned earlier, these tests have not been bought subject to approval by PHE or by the Medicines and Healthcare Products and Regulatory Agency.
The Government paid ready cash for them.
They belong to the NHS.
Which presumably means someone thinks they are useful and can work.
So the biggest question of all is whether they will be distributed to the frontline, to hospitals, within the coming few days?
Coronavirus: Everything you need to know