I agree with much of what has been said. For Law, the best two would be Maths (for logic) and History (for evidence and presentation). For Engineering or Physics, Maths and Physics.
So include Maths, Physics and History in your core. Chemistry adds little to either choice. Further Maths is helpful if you want to apply to a top Uni for Engineering or Physics. It's also a heavyweight A level. English Lit would add to Law, but not to Engineering.
I would go for Maths, Further Maths, History and Physics.
If you choose Engineering or Physics at Uni, you will probably be required to undertake practical (bench) work followed by lab reports. If you choose Law the corresponding practical is a moot. Which do you see yourself as more comfortable with?
From your brief description I would not be surprised if you brought Maths, Computer Science or Philosophy into your Uni choices.