I reckon it falls down in the second paragraph
The 2001 census, already hopelessly out of date and easy to avoid for those who find filling in forms a trifle inelegant, numbered us at a little under 59 million.
Hmm, yes, it is hopelessly out of date, that might be why we had another in 2011 that came up with the figure of 63 million
Now, I can accept it being a bit out with people not filling it in / avoiding etc… But not by 14 million
Edit.
There’s about 25 million households, so that’s nearly one extra person hiding in every attic when the census came round.