If your SCSS rule isn't being applied, it's likely to be a mistake in the nesting of the rule.
- Check the CSS file for how the rule has been generated, e.g. .locations-listing .listings > ARTICLE .m-chapels .location-details
- Go to the HTML and copy the selector for where you're expecting it to be applied. This will be slightly different to how you've written. e.g. #main > section.locations-listing > div.wrapper.listings > article:nth-child(12) > div.location-details
- Comparing the examples, I see that .m-chapels is applied to the article element. It is not a descendent.
- Fix the rule in your SCSS, e.g. &.m-chapels .location-details instead of .m-chapels .location-details
- Profit!