Empty Home Premium would become chargeable at 200% of Full Charge! So said Fiscal Phil Hammond. If you've been busy calculating the increased revenue your Council may earn next year, hold your horses. As the change will require a change to primary legislation, the 200% charge might not be lawful until 1st April 2019. So don't count on any extra revenue in 2018.
Are you confident that you actually know how NHB was calculated for 2016/17. I must admit, I am a little lost and therefore quite ashamed.