Local SEO - Website Not Ranking

We run websites for local businesses, exclusively in the UK and generally they rank very well for Google search using good on-site optimisation combined with a well set-up Google Business Page.

Occasionally however we find a site struggles to rank.

I am looking for a local SEO expert who can analyse a site, identify the problem, and fix it. These are all local businesses optimised for local, low-competitive search phrases.

Please be aware I am NOT looking for link building service. The issue will either be on-site SEO or in some way linked to how Google views the site which is clearly not right.

The first website I would like you to take a look at is a steel/metal fabrication firm based in a UK town of population 100,000. It should realistically be high on page 1 in search but for some reason it is ranking very low, and has been for a very long time.

All websites, domains and businesses are well established and "aged" so this will not be the issue.

I am looking for both an SEO audit, manually done by someone who really understand local SEO, and someone who can give point-by-point instructions on how to fix the issue.