The way I understand the question is it’s asking ‘why you’ and ‘why 
Macfarlanes’, but not in the traditional format or structure. 😅
I guess the main objective is demonstrate your interest in 
Macfarlanes and your suitability as a future associate at the firm.
I would approach it with the following things in mind to form a basic answer. I don’t think there is a single way of answering it though. 🥲
1) what experiences I have (e.g., legal advice clinic, internships, insight days, part-time jobs, society roles, volunteering, etc).
2) what skills, competencies, values and other qualities I have gained from these roles that are transferable to a career at 
Macfarlanes.
3) how do these things align with 
Macfarlanes and demonstrate that I belong at their firm i.e., why me and tie it into why their firm.
4) are there certain aspects of the firm e.g. TC structure, specialist seats, business strategy or firm culture that I resonate with and why.
5) bringing everything together, why would you belong at 
Macfarlanes over any other firm such as 
Travers Smith or 
Slaughter and May.
Ultimately, I would write it assuming the reader knew nothing about me or my motivations but knew everything about 
Macfarlanes. 🥲
The task would be to show a strong alignment between myself and 
Macfarlanes and how I am someone that belongs at the firm. 😅
The answer should be so specific and tailored to 
Macfarlanes that if you removed their name, it would still be clear it’s about them.