Wow just reread this, no wonder you couldn’t help, my bad.
I’ve done some digging since I posted this, it seems that either our custom theme, or another plugin called advanced custom fields is stopping the images from being lazy loaded, and this is with every plugin i’ve tried as well as custom JS.
I tried using this javascript to see if I could find out where the problem is occurring. The observer window manages to correctly identify when it’s coming close to an image, but the actual lazy loading of the images isn’t working.
I’ve since passed this on to a more experienced dev as i’m pretty new to all this, and since the problem seems to be coming from elsewhere rather than your plugin i’m happy to mark this as resolved, but before I do is there anything obvious that springs to mind that we could try?
Thanks for your time
Josh