The quid pro quo

Last year, the British government turned a blind eye to corruption and shut down an investigation into allegations that BAE paid the Saudi royal family hundreds of millions of pounds in bribes to secure a multi-billion pound arms deal in the 80's. Today, the Saudis have anounced that they will be buying 72 Eurofighters at a total cost of 20 billion pounds. I wonder how much their corrupt monarchy is getting in kickbacks and slush funds for that purchase?