Hi Sophie!
I just tweeted you but then thought this might be a better place to share my thoughts.
Firstly, congrats - this is really great work! I think visualisations can be extremely potent in exposing cronyism and other corruption.
I was wondering if you were aware of https://littlesis.org/ ? It's an awesome project for crowd-sourcing data on and connections between powerful people and organizations in order to bring transparency and shine a light on murky areas. As you can see from their data summary, they have an enormous database already.
They also have an Oligrapher graphing tool which has some similarities with yours, although of course some differences too, e.g. it is designed to enable non-technical folk such as journalists curate and collaborate on their own visualisations (which are obviously small subsets of the huge littlesis database). I think Oligrapher also has some low-hanging fruit in terms of simple UI tweaks which could be made to vastly improve the usability, for example zooming with the mouse wheel just like My Little Crony already allows.
I have no affiliation with LittleSis, but I've been very impressed by all their technical and organisational achievements so far, and I think the more that people working in this area can combine efforts, the more powerful the whole movement can become.
By the way, very cool to come across another ex-Oxford maths graduate in this space ;-) Sadly I left academia a lot earlier than you, but I've been working with Free / Open Source software since I discovered it as an undergrad, and in the last few years have become quite involved in the UK political "hacktivism" scene (legal activities only!)