Capital Gains on previous shared ownership

[tax81]

I am hoping someone can help me please? I am trying to see if I need to pay capital gains tax on a previous shared ownership property that was my home from April 2003- Aug 2016. Rented out from Aug 2016-Sept 2019.

BACKGROUND:
A 50% share brought in April 2003 for £62250
25% share brought in 2010 for £30000
25% brought in 2015 for £25000

Total -£117250

Sold in January 2020 for £11500 so a loss of £2250. Despite the loss, am I calculating the capital gains on the total I paid for the property (£117250) or the original price I paid (£62250), which would be a gain. The reason I ask this is the land registry only shows the original purchess price in 2003 and the sold price in 2020

Any help would be much appreciated
thank you

[maths]

You have sold an asset, namely, a 100% interest in a property.

Any capital gain/loss is calculated on the difference between the cost of the 100% asset (117,250) and sale proceeds (115,000).

[tax81]

Thanks very much for your response.

I have another question, do I have to report the loss to HMRC? I know longer need to do a self assessment as I made less than £2500 on the buy to let before I sold it so not relly sure how to close account

Thank you