Mother owns house valued at £150,000 free from mortgage.
Son owns house valued at £225k with £100k mortgage. Son pays £30k off mortgage from own funds and mother gives son £70k to fully repay mortgage.
Both then decide to swap houses by way of two deeds of gift for nil consideration.
Is this effectively an exchange of properties and SDLT is chargeable on both transactions at the values of £150k and £225k?