In relation to the previous example, assume now that Alice always let her Derby house when she was not resident there. Compute the chargeable gain.

Data from Example 2

On 1 June 1995, Alice bought a house in Derby for £45,000.
She occupied the house as her PPR until 1 May 1997 when she left to work in Exeter,
living in rented accommodation.
She returned to the house in Derby on 1 November 1998 and stayed until 1 July 2001 when she left to take up a post in the USA, again living in rented accommodation.
She returned to Derby on 1 February 2004 and stayed until 1 June 2015 when she bought a house in Nottingham and made this her principal private residence.
On 1 February 2018 she sold the house in Derby for £164,000.
Compute the chargeable gain.