i say economics!
as said above, if u have a thorough knowledge of economics, u are eligible for management in engineering (although they also teach u management at university)
n a level computing sucks cuz it has no credit whatsoever. even if u want to do computer engineering, u dont need computing in a level, only math and physics. u also have to do 2 projects which r time consuming (which is why im nt takin computing in a level)