You're doing plenty, what you need to do now is reflect on those experiences and think about how they relate to your interest in the subject. Remember the personal statement is not just a list of things you have done, they want to see you critically reflect on those and that you have taken something away from the experiences.
Also I'd note that chemical engineering involves very, very little chemistry. It's about 70% maths, 20% physics, and maybe 10% chemistry at most. If your main interest is chemistry, chemical engineering is not likely to be a suitable alternative. The one possible exception is the joint honours course at Strathclyde in applied chemistry and chemical engineering, but bear in mind the chemical engineering side is mostly maths.
I'm not aware of Warwick being especially well known for chemistry (it's better known for maths/economics/business/CS). I'd suggest considering places like Southampton, Durham (via Natural Sciences) or Bath which have very good chemistry departments/courses as well or possibly instead (unless you are aiming to work in investment banking, in which case Warwick, being a target uni, will be a better option - for anything else though I'm not sure the department compares that well to those others?).