Written work for Music at Cambridge

Hi everyone, I'm applying for Music at Cambridge and the deadline is fast approaching! I'm struggling with deciding what to submit. King's asks for either a Bach chorale or composition, and an essay. Essentially, all of my written work is from Year 12 but I don't think a lot of them are the best I can do, even though they were marked well.
I have a Bach chorale that was marked by a teacher but am unsure if it's my best work as I'd never done Bach chorales before and he had to help me a lot on it. I also have a composition that I wrote for my Year 12 mock and was marked well, but I don't really think it's Cambridge standard.
For my essay, I'm worried that it's too short. I know that they would assess the work within the context of the conditions provided, but the two best scoring essays I've written are only 400 words each. I have another essay that I wrote at home that is around 1000 words, but scored much less than my other two essays.
I'm mostly worried about the essay. Even though it says on King's website that they just need one essay, should I submit both of my best ones, or just submit the 1000 word essay even though I think it's not as good? And for the actual format, I don't have access to a scanner, so can I type up the essay and write out the teacher feedback, or should I take photos of my written work and submit those?
Thanks everyone!