Ofgem produces a quarterly technical monitoring report on measures installed under the Energy Company Obligation (ECO). The latest report was published on 26 July 2016 covering the period October to December 2015.
Technical Monitoring is a compliance regime under ECO that requires obligated suppliers to commission on-site inspections of at least 5% of measures installed in a quarter, conducted by an independent party.
The report finds, for example, that “429 of the 6,878 measures monitored failed to comply with a standard of installation of the measure (~6%).” This is a similar level to quarter two.
See the full report at ECO2 monitoring report