If some one shown me a photo of a flue in a loft secured I would still check .,,,No, HETAS don't need to fit the liner to sign off, but they do need to be the one who finally attaches the liner to the stove. Just leave them unconnected, without register plate, and he can look up the flue to see that the liner is the right way up etc, before connecting. Show him photos of the chimney termination.
Would you rather it done properly and signed off to protect you and family if you have one ,,,,,,, or pay pennies for an illegal fitter ?Last stove installation I had was £900. Stove extra and the regular grade of flexible liner rather than the more expensive. Took two of them about two hours, allow another hour for driving perhaps. Let's say, two people and half a day's work. Quite an hourly rate.
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