Purchased house for £100,000 in 2008
Sold house for £200,000 in 2017
The house was let out entirely for the duration of ownership. My income for 2017 was under the tax free allowance.
Now, to calculate my CGT do I use the data for only 2017 (my income, the CGT rate, capital gains allowance) or do I go back for every year and use a percentage of each year (income, CGT rates in 2008, 2009, etc)