The policies will come with acceptance of the framework (the GND in the USA for instance), and the political will to enforce it will be driven by public demand. The 'how to' is pretty much known in every sector except maybe aviation. We are now really getting to the point where climate will invade every discussion in society. The government can no longer deal with climate as a separate bullet point. It will be all-encompassing and the cost of inaction will be far higher in the medium to long term.
For your own sanity you do need to divorce the efforts of an individual from the efforts of business/state/EU though or it gets a little muddled. Not to put too fine a point on it, nothing you can do will make that much of a difference really. Yes every little helps but the problem is at a scale that needs to be dealt with at the state level. In my opinion the best way you can really effect things is via your vote and voice (but please do the other things too.
Those questions from that LBC interview sound a little misinformed. For instance, ground source heat pumps are not practical so any advice in that direction is frankly wrong, in a domestic situation at least. Air source heat pumps are suitable for most domestic situations and certainly a lot cheaper (though still not cheap enough yet IMO). There are a lot of complexities in an around heat pumps which I won't go into, but the rule of thumb is that you'll get at least 3 units of heat per unit of electricity consumed in the heat pump, so the higher price of electricity is more than counteracted by the efficiency of the system. In short, running a heat pump is far cheaper than a gas boiler in a well-insulated house, though they work less well in old houses.
I think they go hand in hand, similar to Brexit in many ways where people say if you want a certain deal then spell out how to achieve it. The 'How To' might be known but that doesn't mean enough people will be willing to accept it, if people want to push a green agenda then they should also expect their position to be under scrutiny and when challenged they should come up with answers and policy proposals rather than we'll look into various things. The world is far too advanced for that type of on the fence answer now.
And therein lies the rub, the UK has a very old housing stock that isn't well insulated. I'd estimate over half the housing stock is around the EPC D for instance. Again the answers shouldn't be mis-informed, it was a green party MEP in the hot seat who should be well versed in explaining their one and only policy.
