Sorry, I wasn't clear enough. It isn't that they don't work. Its that they need the right environment in which to work. Heat Pumps need a suitable source of heat from the environment and that takes space. Either garden or roof space and lots of it, especially the further north you get (or south in your case 
). We are above 53Ā°N, roughly level with Newfoundland. The equivalent down your end of the world would be 1,000 km south from the southern tip of Tasmania (over a 1/3 of the way across the Southern Ocean to Antarctica).
Also, many houses in the UK are tightly packed with small, often overlooked gardens and many houses are quite small. Here in Sheffield, the majority of houses are terraced, often with postage stamp gardens and the hills are steep.
Heat Pump based heating not only needs significant surface area to collect heat but also needs highly insulated houses (at least in this climate) - something that is extremely hard to achieve in small Victorian terraced housing.
Unfortunately, most of our government live in large properties with large gardens in the South. They will have no problems at all converting to heat pumps. But 10's of millions of people in the UK don't live that way. Even in our house - which is quite large for Sheffield and has a decent garden - we really struggle to get good insulation having solid stone walls on 2 sides and solid brick elsewhere and we are exposed on 2 sides being high on a hill. Because of the steepness of the terrain, our garden isn't really suitable for heat collection either since, for much of the year, it is in shadow.
Area heating is another option but is poorly suited to cities with steep hills. The other side of Sheffield does have some area heating based on the incinerator and that services a region of flats. But the terrain there is very different to where we are. Other northern cities are even worse off.
I'm more aware of that than most people and I've been having some discussions with our energy provider. But ignoring reality isn't going to help anyone. We have to back the technologies that work, not ones that don't in our case.
The UK has long had a serious housing crisis that means we are 100's of thousands of dwellings short already. Nobody is going to be suggesting widespread clearance of existing housing stock - we did that decades ago to get rid of old slums. Focus is on new housing and rightly, there is now finally a bit more focus on getting them better insulated from the outset.
Figures from 2010 show around 22.4 million dwellings in the UK, of which some 6.9 million didn't have cavity walls and 64% of these "had building features that would probably make the installation of solid wall insulation more expensive or problematic". Around 22% of dwellings were built before 1919. Around 22% are flats.
I'd be delighted to move away from gas heating and I'm always on the lookout for what is happening with alternative heating, but we have to be realistic as well.
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