During last winter gas heater servicing I told the plumber to set the unit to 50°C heating water output so I could check if the heaters would get warm enough with a heat pump. 1,5 hours of discussion about old buildings and heat pumps resulted till he complied.
It was just a test setup that could be reverted any time.
I would like to have someone installing the thing who is motivated like the folks in the article. Motivation=good work=probably an efficient system. But these seem to be hard to come by here.