Do you have any independent reviews of your installation service?
Make sure you check the credibility of your installer and the fire sprinkler product manufacturer. A quick Google search ("Installer Ltd" reviews) can reveal independent customer testimonials and uncover any persistent bad practices.
Plumis authorised installers use Google, Trust pilot or Feefo reviews. Feefo, for example, 'isn't your average reviews platform. We want the businesses that work with us to provide their customers with feedback that they can trust, so we work hard to ensure that the reviews we collect are real people's honest opinions.