There was a gap of around 20 seats through the Bullens Stand (Upper/Lower) & Paddock - that's around 1,000 seats. Then there was at least another 200-300 unsold severely restricted view seats - so that's at least 39,600 if my estimate of the gap is accurate. Therefore pretty much a sell-out.
Oh yeah the gap of seats. Forgot about that. That'll be most of it.