Well you could start with the magazine Private Eye who run a regular column on "Rotten Boroughs". Other organisations attempt to trace Local authority corruption.
If you are looking for a more general survey you could read the report on Mounting Risks of corruption by transparency international.
Or if you are looking for the government policy there is the Local governemnt counter fraud and corruption strategy 2016-2019
Roughly to sumarise these documents: Corruption is a problem, and a growing problem. However it is currently mostly small scale. The government is aware and does have a strategy in place.