I bought a house in December 2013. In November 2015, I bought a second house and it was registered in my name, February 2017. The intention was to let out the first house, and we moved March 2016, with the first house now being empty. However, in the meanwhile, I decided to sell the first house. I haven't had any tenants staying in the first house, it has been empty for a month now. We stayed in the first house since I bought it, for over two years. Will I be liable for capital gains tax, or will the first house still be regarded as primary residence, since I didn't have tenants there?