We seem to have got hung up on the bilateral being a problem when it appears it isn't, at least as things stand.
I will have to see if I can quote an external source, but, the email I have seen and has been circulated amongst several other sources reads, and, this is a direct copy and paste:
''Air China has already spent £625,000 seeking an addendum to serve Manchester, to which they have the rights to serve from the CAAC (granted in 2009), but cannot start services at this time as there is no room in the current UK-China bilateral''
Now, given cargo flights are covered in the bilateral, the fact Manchester has been served by Air China shows MAN is one of the 6 points allowed in the current bilateral. Given there is room right now to start a flight, I am genuinely at a loss as to why Air China are reportedly having such an issue that they have already parted with that amount of money.