Paul Ayris and Lara Speicher have published "UCL Press: The UK's 'First Fully Open Access' University Press" in Insights: the UKSG Journal.
Here's an excerpt:
UCL Press first came into existence as a commercial publisher in 1991, reaching its zenith as a publisher in around 1996. After that, activity diminished and publishing effectively came to an end. UCL Press was relaunched in June 2015 as 'the first fully OA university press in the UK'. It forms a substantial contribution to the UCL 20344 strategy to deliver UCL as an accessible and publicly engaged organization. It also feeds the wider global move towards open science. UCL has a reputation as a disruptive innovator, and the relaunch of UCL Press carries on that noble tradition into the 21st century.