Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
Dettol has been a family favourite for years - cleans the dirt you can see and the germs you can't! Just don't get too over the top with it though... a little dirt is good for the immune system and no one wants super bugs!! Gotta love the eucalyptus oil too!