The boiler has to go under the BUS grant scheme.I wonder if Octopus would allow a dual setup, both Gas and a new heat pump?
The only reason to go down the hybrid route is that your heat loss is so high, it couldn’t be covered by a heat pump (or multiple) or there was insufficient power to install a high enough power heat pump.
Why would you want it to stay? If the units installed correctly, you don’t need it.
#off topic - go to the linked thread.