Hello, @MrTailor,
You are right, there is no such option to change the height/size of that for a single category only, so you have to try with the Custom CSS code, Please inspect the particular product category page and then copy the product category page unique class number as shown in this screenshot: https://ibb.co/W6k6YX1 after that replace the product category page unique class number in the below-listed code and paste the below-given code to XStore >> Theme Settings >> Theme Custom CSS >> Global CSS, it will apply on that particular product category page only.
.tax-product_cat.term-43 .page-heading {
height: 550px !important;
}
Regards 8Themes Team.