You're welcome!Thank you and to everyone else who replied as well.
Their cover letter is limited to 300 words only, which is why I asked in the first place. Because they sort of set out what they are looking for in the wording of the question, and with such a limited word count, I wasn't sure if I should/can include much on "why law."
I would have followed the "why law" "why firm" "why me" structure in a longer cover letter.
It can be really tricky when you're restricted to a small word count. However, one of the key skills a commercial lawyer will have is a good command of written communication. Lawyers are required to summarize their legal advice/opinion in a comprehensive way that is digestible to the client. So I think when it comes to drafting your various apps, it can help you work on being more concise. You'd be surprise at how many words we can waste sometimes that don't add any further meaning/value to our overall answer! That being said, it isn't easy.. it's a skill that we all have to work (myself included!) - Wishing you all the best of luck with your app!