As someone said, it wasn't really in the know City information, just Colin trying to piece things together. That was because of something in the emails about 'H.H securing funding from elsewhere' which was being used as a smoking gun argument.
Someone will be along to clear this up properly no doubt but from memory: I believe there was a belief, based off the open skies court case that involved Etihad, that ADEC(Abu Dhabi Executive Council?) 'likely' paid the money. H.H(His Highness) was said to be a different Royal, who is actually involved with Etihad, at CAS(so Colin was correct about that and it makes much more sense too). So that wouldn't be disguised equity and it wouldn't have involved Sheikh Mansour authorising payments from government funds. However, there may have still been an argument that the accounts weren't showing an accurate reflection of where the money came from, according to some(I seem to remember Der Spiegel made an article exploring that angle of attack).
It was a well reasoned theory and I certainly appreciated reading that take before the CAS hearing. If only to show the know-it-alls, that what was said in the emails could mean any number of things(not just what our rivals wanted it to mean) and only City truly knew the correct context, not Der Spiegel, not UEFA.
However, at CAS, we found out that £8m came from Etihad's marketing budget/fund, the rest came from Etihad's central funds. I believe they even showed accounting data to prove it but I could be mistaken. CAS accepted this explanation either way.