Such shoddy work...
First, no link to the study. SRSLY?!?!?
Second, no info on how many or what percentage of black people there were in the area studied.
I would be surprised if there were a lot of people we consider black (eg, Sub-Suharan) in the UK during the plague as the plague occurred more than 50 years before the age of exploration in which Europeans started sailing long distances, such as to sub-Saharan Africa, and even then, it was the Portuguese who went.
Third, no indication if actual results, such as there were 1/4th again as many black people in the plague cemeteries as would be expected from the population of black people at the time, and this was reflected in the lower number proportionately of black people in non-plague cemeteries.
Get a grip, BBC, lest you provide evidence that you are a mere propaganda machine for the extreme left.
I would bet that the non-Anglo-Saxon population of medieval Britain was at most a fraction of 1%.
There might not be any quick way to check this though as everything I can google will be full of lies.
I would guess that most of the movement of people from Africa to Britannia during the Roman Empire, and even much later were not black, as we know it today.