Howdy!
The title is indeed too long, and I recommend shortening it.
You can adjust various title parts for the homepage at “Homepage Settings” under “General” and “Additions.”
Under “General,” the Meta Title input field should preferably be empty. The default value is your “Site Title” entered at “WP Admin > Settings > General”, which should be the brand name. I think “Energy Performance Certificates (EPC) and Home Energy Efficiency” is far too long for an official brand title — isn’t the brand name “EPC Eco Bunny”?
If you wish to keep the “Site Title” that long for any reason, then I recommend entering your website’s shorter brand name at “SEO Settings > Title Settings > Additions > Site Title.” The SEO Framework considers this entry the website brand name.
Lastly, at “SEO Settings > Homepage Settings > Additions,” you can add anything you’d like to explain the homepage better. Here are best practices for creating a good title: https://developers.google.com/search/docs/appearance/title-link#page-titles.
The Meta Title input field under “General” depicts how the entire title will appear to search engines.
I hope this explains everything! Have a lovely day ??