Hey dudePretty much the same content is covered, you will miss a few electives here and there (which has to happen if you want to get 2 degrees in 5 years when separately they would take 7 years) but nothing significant enough to make a difference.
By the way:
I've been telling people not to bother to do Engineering if they are doing only General Maths. People have been telling such people that the unis offer Summer School as well as bridging course; so they should be able to pursue Engineering without higher level Maths in their HSC. Since you have done so many Maths units already in your Engineering course so far, you have the real experience. What do you think? Can a person doing just General Maths pursue Engineering?