That is amazing that you know exactly what tests they are using despite it not reported in the article.
This means you used a secondary source. Awesome! Can you provide that source please that the UK is using “discredited” PCR tests and using that data to determine there is a variant of covid-19?
If you cannot then what you’re positing is pure conjecture.
Furthermore, if these tests were discredited as you so claim, why would they continue to use them?
And who discredited these tests?