The low-level cistern for traditional toilets is fixed just above the toilet pan and usually have a gap between them and the pan. One more style of the cistern is set high up on your wall above the pan. Ideal Standard cistern is the latest model cistern liked by most homeowners due to its comfort and simple features. https://www.mytoiletspares.co.uk/cistern-spares/ideal-standard-armitage-shanks-cistern-spares.html