The presentation will cover final results from the multi-method methane monitoring campaign at a 100,000 PE WRRF with AD and biogas upgrading facility. It builds on last year's presentation which presented initial results and provides over 12 months worth of work. Two site wide quantification approaches were deployed - tracer correlation and FTIR with inverse dispersion modelling. A continuously monitoring Lidar was also employed for coverage across a majority of the site and discrete measurements with optical gas imaging, hiflow sampler and flux hoods were undertaken. The results provide a site level quantification as well as point source quantification and a hierarchy of mitigation measures which were recommended. Low cost metal oxide sensors were also trialled. Quantification results were compared across methods and measured results compared to utility carbon accounting using the recently developed WRF5188 Water Sector Climate Emissions Quantification Guidelines. Comparison to European including UK work will also be discussed in the presentation - highlighting opportunities and challenges and latest approaches to methane monitoring.