At replacement toiletseats.co.uk we have sourced a range of universal replacements for non-standard toilet pans.
When considering seat measurements please note that these should be taken from the toilet pan rather than off seat.
These measurements should be for
Length - centre line of the hinge hole to the front of toilet pan
Width - At widest point side to side
Hinge holes - Distance between holes assuming mid hole to mid hole.
Manufacturers normally display measurements assuming this