I'm a co-founder of Regulation Technologies Ltd, we're on the Neo4j start-up programme with our product https://riskhunter.co.uk/ which identifies fraud and mis-selling in UK financial services.
I first came across graphs with a previous start-up (riskopy.com sold 18 months ago, we identified hidden risks in supply chains) and have been hooked ever since.
We maintain a neo DB of all past and live UK companies and company officers and may be able to open that up for community access at some point (12m companies, 13m officers, 180m relationships, 20k records updates daily, spatial and temporal data included). Check thegraphproject.com periodically to see if we do...
And lastly, we are recruiting for a meetup group https://www.meetup.com/Bristol-Graph-Database-Group/ in Bristol. UK. Hoping to start events next year.
Just for the record, I am not tech founder - I do the other stuff
Looking forward to being involved.