Firstly, it is important to note that keyword stuffing, or excessively using the same target keyword in your blog posts or other content, can actually harm your rankings rather than improve them. Google's algorithm is smart enough to recognize when content is over-optimized and may penalize your website accordingly.
That being said, it is still important to include relevant keywords in your content to improve its visibility and relevance for search engines. Instead of solely focusing on location-based keywords like "interior designer in Cheltenham," try to incorporate a mix of other related keywords such as "interior design tips," "furniture guides," and "paint color advice." This way, you can attract a wider audience who may not necessarily be searching for a local interior designer, but are still interested in interior design-related content.
Regarding your blog post about your trip to Copenhagen, you could potentially use a more general keyword like "interior design" or "design inspiration," but it would be best to also include location-based keywords such as "interior design in Copenhagen" or "Copenhagen design trends" in your content to help boost your local rankings.
In summary, it's important to strike a balance between incorporating relevant keywords and avoiding over-optimization. By including a mix of location-based and general keywords in your content, you can improve your visibility and attract a wider audience to your website.