Negative reviews are usually from students who were hoping to get high grades with little work.
The number of international students does not affect the number of UK students admitted, because universites keep a number of places for international students and only offer them places intended for home students if they cannot fill those places.
UCL has the Integrated Engineering Programme, which is a project based programme. Read more about it and see what you think of it.
All engineering is Maths and Physics based, so if anyone wanted to do more chemistry the should have done a degree in chemistry and not engineering. Chemical Engineers work mainly on industrial processes.
Chemica Engineering at UCL was until a few years' ago a recruiting department (they had fewer applications than other departments, and therefore had to actively recruit students). This has changed in the past couple of years, as Chemical Engineering has become more trendy and they receive more applications than they used to.
If QMUL will accept you, go there. If you still want a degree from UCL, apply for a master's degree afterwards.