The novelist has never mentioned such an "anecdote", They may be connected to the same family tree, but a very close connection seems impossible. They both are distinguished scholars of the UK, and if that is the case, the public would publicize that relationship on their behalf. And I did not find anything like this on the internet though I did wish to see something interesting and legendary about these two celebrities of the same last name.
Had I not done the search, a good wish may have lived on in my mind though it is a trivial one:)