The boiler upgrade scheme is a UK Government grant for people in England and Wales who want to install a heat pump or a biomass boiler.  The Boiler Upgrade Scheme covers three low carbon heating systems. The level of grant towards a heat pump increased from £5,000 to £7,500 on 23 October 2023.  The scheme is scheduled to run until 2028. 
https://www.gov.uk/apply-boiler-upgrade-scheme