Very slick site, easy to browse and a smart image.
The only addition I would have is the ability to select a category once on the page is populated with results for the category you have selected. Basically meaning you can navigate the categories from the results page i.e. select 'excavators' at the home page it then displays results for Excavators, but leaves no quick way to view the other categories such as Backhoe or Dumpers etc... Without clicking back to home page or construction machines which then populates the whole page with all your stock. A potentially large amount of pages, when all you were after was backhoes. But that is just me being picky...
Very professional effort so far, I'd be very pleased if this was my own site. I'm sure on the final revision a security certificate will be produced for the site so it displays as a secure page. Maybe also see what is required regarding GDPR, when taking information on the sites 'Machinery Wanted' page.
Well done so far, it gets the thumbs up from me.

No clutter or unnecessary bling, should render well on most devices.