Buzzardo - your analysis doesn't address cash buyers - of whom their are many in the UK and among overseas investors. The doom and gloom stamp duty stuff doesn't have that huge an impact in the lower end of the market. (Instead of paying £0 stamp duty on the last place I bought, under the new rules I'd be paying £3750 - about 4 months' rental income on a house shared by three young, working tenants. I'd rather not pay it, but it's not exactly Everest.)
Those overseas investors, by the way, are still free to buy - rather than bar them / put a further financial levy on them / require them to seek licences to purchase a particular property a la Austria, the Gov't has chosen to go for local landlords. We may be part of the problem, but there are rather more obvious targets out there. The Gov't's failure to even consider that kind of move seems to suggest that they're more interested in making a populist gesture against the small-time landlord.
(They might also, if they were that way inclined, make moves to check LL affordability, as they did with the rest of the residential sector. That's a much more sensible, less populist approach. They haven't done that. That's likely coming in, but only thanks to European regulations coming in soon.)
I'm up for a reasoned debate on this, but the Range Rover-driving spiv (I have a sedan not much younger than me), greedy, overleveraged (it's 60% across my portfolio, with all mortgages being repaid), tax-avoidant-bordering-on-illegal rhetoric (I'm a solicitor) is a complete straw man. Frankly, if your hypothetical overleveraged spiv doesn't realise that taking on that much debt may be risky, let him or her wait and see what the market dictates. We're not all Rachman figures.