This sounds like pretty much what happened. This third party ownership seems to have reached epidemic proportions! http://www.guardian.co.uk/football/2012/sep/04/tottenham-hotspur-joao-moutinho
You'd think AVB may have remebered the deal Moutinho was on at Porto...he was involved with it! Why did this 3rd party thing become a surprise issue at the end?
Who knows but he did say it was very difficult to buy players from Porto. Knowing about the third party is one thing, knowing how they are going to react another. It would be reasonable to assume they would be keen on a player move considering they get a cut of the deal. No deal no profit so they must be holding out for a bigger price, maybe thought Zenit would provide it.
I do not like seeing VDV in a non-Spurs shirt. Everyone's got grumbles about the last few weeks' activities and games but selling VDV to the first OKish offer is just criminal. Rather have 60 mins of VDV than 90 mins of practically anyone else. I think in retrospect this might be seen as a huge loss. Hope not, obviously - I want to be wrong about our personnel/management changes I really do!