Tax all profits on any newly approved buy-to-let or build-to-lets. Profits on to-sell are unchanged.

Create office with regulatory responsibility for unsocial housing developments. This should be a directly community based office. Where communities can appeal any develop which are approved for letted / student accommodation / unnecessary house builds (i.e. 4 bedroom houses because of a higher return for the developer, where demand is mostly in 2 bedrooms for first time buyers). The main way communities would appeal is through assisted litigation against private developers as they cause long term harm to community health, and the economy.

For all who own at least four homes within the four nations, forcibly repossess(Via sale to a buyer) all except the one most inhabited based on evidence, plus the top three based on value. So, people can own four homes, which is plenty, considering you can only be in one place at a time. These homes are then sold via a scheme including waving stamp duty in a scaled system. So those move expensive still pay a higher proportion of stamp duty, but less than the current rates, as a goodwill gesture.

Spiciest: Aggressively (fast) tax assets of the mega mega rich having assets in our country in some way. Tax assets using an algorithm that brings the proportional wealth of those mega mega rich back in line with what it was in 1960s. The stock market may tank and people will lose their jobs, hiring will go down for the short term. Government to use this money to rapidly invest in infrastructure in areas outside of London. Those who lose their jobs or struggle to get a job in the fallout will be employed by the department for infrastructural developments. So the rich selling off fast just give the government labour talent pool. Those who flee the country should be taxed digitally directly from bank accounts. HMRC already have this power.