According to their annual report they've bought a 3rd boiler (not running on waste), but the contract with the 3rd party supplier was up for renewal. I ought to check history of the area as I just noticed an odd gap in landuse. I cant imagine they can operate without supplies of heating & hot water. This is a report of a recent tender (which may be available as open data somewhere) https://www.endswasteandbioenergy.com/article/1661834/hillingdon-tenders-%E2%82%AC60m-efw-plant-deal