SDLT Changes 15th February 2016 +3% Extra Stamp Duty Land Tax: Unless you purchase before 1 April. Property investing clients will be aware than plans for a 3% stamp duty land tax surcharge for property purchases over £40k of second homes and buy-to-lets are due to come into effect on 1 April 2016. This leaves a small window of opportunity now to exchange and complete before these tax rules change. Related Services Tax Planning