Hi Dom,
Thanks for the speedy reply.
The image in question is not part of a plugin although this is a more widespread issue whereby lines of code (gained from inspecting the web page) are not present in the theme code editor.
I also cannot find a single instant of the word ‘priority’ in my theme editor (a phrase I believe is part of code to set fetch priority).
It appears as though there is another ‘hidden’ level of code between that in my theme editor and that in my actual web page as the two do not seem to match up.
I paid £300 for the theme recently so would rather avoid ditching it if possible.
I’m still hoping to get to the bottom of the issue myself through pure stubbornness but could you give an indication of how you charge for services? Do I give you access to the site so that you can weigh the job up and give a quote/estimate?
Thanks again