So, bearing in mind the pitch is in the same orientation and the new stadium is clearly much wider, do you wish to reconsider your statement? (It's longer, too!)
I'm a Chartered Quantity Surveyor, too, but it doesn't make me a structural engineer!
However, my experience, common sense and knowledge of the structure that was erected makes it pretty clear that the roof is going no higher, so no higher tiers can be added.
I would suggest that Richard Hebbard probably knows very little more than you about that possibility.
I don't know how many times others have to tell you (it feels like every week), but he was and remains completely wrong.
Take a look at the additional land take at White Hart Lane to see what...