...and what's new this Saturday morning, dazzlenation?...well, I was to come across another acronym for CHP....along with a document (march 2018) that is *'d upon the timer system....go figure:

https://www.london.gov.uk/sites/default/files/NHSPS%20NHSE%20NHSI%20and%20CHP%20-%20Indigo%20%283029%29.pdf