I have just noticed the 'Google Sitemap' is being generated using HTTP, but the site is HTTPS, base URL is set to HTTPS, so I am confused why the sitemap would not generate using URLs that are HTTPS?
Most likely because the google sitemap doesn't need to be in https mode for google to use it. You can still gain access to the file in HTTP and HTTPS. The file does technically live outside of Magento.
Most likely because the google sitemap doesn't need to be in https mode for google to use it. You can still gain access to the file in HTTP and HTTPS. The file does technically live outside of Magento.