Having watched it at home (better sound system), I can safely say that wasn't Hammond...
But it's not Hill, although it's definitely English...
Some people seem to think it's more than one person, but I don't think that rumour was ever confirmed, other than Kovalainen and the odd other tester standing in occasionally.
The chances of us (LFS Forum) getting it right, when almost every other car forum in the world has exactly the same discussions are slim, so I say forget trying to work it out and just enjoy it for what it is - entertainment...