I'm more interested in what the article says about "opposition research" in general.
I suppose I assumed that – although a US term – some version of it had long been going on in the UK, with the whips' offices knowing where the bodies are buried and candidates for high office being invited to tell their team about the skeletons rattling in their closets before the press did it for them.
So I'm mildly interested to learn that, while "not uncommon" in Tory leadership campaigns, nor is it standard.
Perhaps the speaker just meant "not uncommon" to commission a professional company to do it.