At replacement toiletseats.co.uk we have sourced a range of universal replacements for non standrd 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 hinge hole to 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