As part of a stove installation
If a stove is to be installed with a flexible stainless steel liner installed into an existing "used" chimney then this will be the last chance to sweep the chimney before the liner goes in. After the liner is in place it will only be possible to sweep the liner but not the chimney.
It's important that the chimney is swept before the liner is installed as this will ensure that the chimney is free from sooty and tarry deposits which may cause smells when in contact with the hot liner, or possibly even a fire. It also proves that the chimney is clear and able to accept the flexible liner. In some straight chimneys this can be seen but in those with bends it is a way of checking all is clear.
This is something to discuss and arrange with our surveyor on survey so that it can be included and quoted for as part of the installation package.