Regardless of how genuine the person may appear, ask for a leaflet with the company details.
Always do a check online, and on the TrustMark website, to ensure the details you’ve been provided with are genuine.
Any installer offering to complete work of this nature must be licensed with TrustMark for the relevant categories of insulation that they have been approved to do. These include external wall, loft and floor insulation.
Remember any deals that seem to good to be true normally are, don’t be rushed or pressured into signing up to anything or agreeing any works.
Say NO to traders who come to your door without being invited.