[Avid Covid (OP)]

R0 is the expected number of cases directly generated by one case in a population where all individuals are susceptible to infection (quoting wikipedia)
I believe R0 is around 3

At the time of the lockdown I assume someone estimated how R0 broke down by activity in order to assess the impact of eliminating some activities in order to bring R below 1
Examples of activities could be 1) attending large gatherings 2) schools 3) grocery shopping 4) visting friends and family 5) hospitals 6) pubs & restaurants

I'm also interested in the estimated impact on R0 of hospitals lacking adequate PPE and testing facilities

[set fair]

You're right, the modelling, on which the UK government based its strategy, was done at Imperial College. You'll find some of what you want at https://www.imperial.ac.uk/media/imperial-college/medicine/sph/ide/gida-fellowships/Imperial-College-COVID19-NPI-modelling-16-03-2020.pdf you may have to look further around their website. When you just want to find a few specific things you still have to wade through a lot of stuff.