Current government/NHS line is:
When to get a test
Get a test as soon as possible if you have any symptoms of coronavirus.
The symptoms are:
a high temperature
a new, continuous cough
a loss or change to your sense of smell or taste
The test needs to be done in the first 8 days of having symptoms.
You do not need to get a test if you have no symptoms or if you have different symptoms.
But if the same is happening here as reported in this Irish article www.irishtimes.com/life-and-style/health-family/irish-gps-fighting-third-wave-covid-on-the-front-line-of-the-world-s-worst-outbreak-1.4458430?mode=amp
then it looks like this new variant may often have different symptoms to the standard 3 - lots of people with no cough, and no temperature being reported. Who the UK guidelines say shouldn't be tested.