A gas boiler that can burn 30% hydrogen is less than £3k. I just bought one, and the cost of the heat pump was £10k. Plus electricicty is at least 4x more expensive than gas, so there is no saving.

The economics just don't work. No one is going to replace their existing boiler with a heat pump.

Converting gas turbines to burn hydrogen is a good idea. We need multiple solutions to transition. There is no silver bullet