How do I calculate Private Residence Relief for a house I've sold where there was a loss, not a gain? (opens in new tab)

This question is likely specific to UK rules. I've sold a flat which I lived in for part of the time I owned it. I'm trying to fill out the Inland Revenue's 'report my Capital Gains Tax' form. I've read the rules on Private Residence Relief and I think I understand how to calculate the proportion of the gain that applies to me (which normally apply to the amount of the gain I believe). However, in my case, I only made a very small gross gain on my property, and in fact overall made a small ne...