You will probably appreciate not all chimneys are the same. 
The prices listed reflect the difficulty, equipment and time needed.

A lined flue stove or open fire routine sweep £65

An unlined flue where soot doors or inspection plates need removing to enable cleaning £75

Solid fuel cooking ranges and heaters £75

Extra large fireplaces / taller properties £90

You may be advised of any safety defects that exist and offered repairs for these to achieve a certificate. 
Examples could be the use of fire cement or silicon, rope seals, fire brick replacement, glass, other minor repairs.

Any addition work will be chargeable and agreed with you.