Stove installation, building control, and installation by a hetas installer

Flue outlet heights - in Document J, pages 25-27

Stove installation

If you are relining your chimney whether that be with flexible liner, pumice, or concrete liners or if you are building a new chimney (including building a new chimney using twin wall insulated flue pipe) then this is classed as "Building work" and you must notify building control before work starts.

In any case there may well be local planning restrictions convering chimney work and new chimneys that you have to follow.

Such work has to be done under the guidance of a building inspector or by a HETAS installer.