If you look at the below, it does seem that the U.K. is testing more each day. The latest date I can see is 5th April. If anyone knows a more up-to-date record I would be curiouS.
www.google.co.uk/amp/s/www.statista.com/chart/amp/21316/people-tested-covid-19-uk/
Given that the absolute number of positive tests has been stable, I would have thought we should have peaked in new case numbers.
If you believe the lockdown was a success (as I do) the peak of new administrations should have been 4th April (incubation mean 5 days, hospital admission and testing day 7 of disease). The peak death would be about 15 th April (admission +11 days).
It will be messy but this, to me, broadly squares with what we are seeing. There is no mechanistic reason for a much later peak and I suspect the data, when viewed retrospectively, will support these types of peaks.