It's the BBC. They make mistakes, but it is entirely reasonable to start from the assumption that they have not made such a big mistake.

Anyway, here's a publication about the study that makes it pretty clear that they got it right (abstract only, paywall):

https://www.nature.com/articles/nbt.4114

(I found the study by assuming a page like http://www.thelondonproject.org/ would exist and then following the link provided)