Well for a start how about making transfer passengers pay APD tax so they actually contribute something to the UK economy rather than just the bottom line of a few network airlines ?
That's an interesting one, which is in fact addressed (and dismissed, in the short-term at least) in the report:
"Apply (APD) to transfer passengers:
This proposal would change the rules surrounding Air Passenger Duty so that it applies to passengers connecting via UK airports without leaving the ‘airside’ area of the airport.
The Commission did not feel that the emerging analysis on the value of transfer traffic had made a case for this measure at this time."