Lol Cadbury's world helps secure PEK link? Really?
I'm not turning this tribal as I'm not a born and bred Manc but I really don't see that. BHX has it's own attributes to attract a PEK service but Cadbury's world isn't one of them.
As for MAN. Well you have to remember that few northerners would consider BHX, they'd probably rather connect elsewhere from MAN than travel to BHX. I wouldn't place too much emphasis on the extended runway at BHX either. In the past, it has still struggled to get long haul routes that were possible on the runway. Meanwhile, others have been lost. I.e ORD with AA.