As you may be aware many insurance companies are requesting that range ducting extraction systems need regular cleaning, as well as your annual range service.
Flue cleaning is essential to help prevent fires in extraction ductwork which is a common occurrence that causes millions of pounds in damage and insurance claims each year. Many insurance companies are aware of this and insist on a minimum of annual cleaning by specialists, some offering a discount if it is done more often.
Previously range servicing companies cleaned ductwork by scraping out grease that could be reached from access holes. This meant that only 2-3 metres of grease would be removed where as a typical range has more like 12 metres of ductwork.