Seat portion of a seat

A seat portion for a seat, which seat portion comprises at least a first part which is made of a first plastics foam material of a first hardness, and a second part which is made of a second plastics foam material of a second and lesser hardness:

• and in which the second part is in the form of an insert which fits into a complementarily shaped recess in the first part and does not extend into a backrest portion for the seat;
• the recess extends from an upper surface of the first part towards an opposite surface;
• the recess does not extend through said opposite surface;
• the recess having upwardly facing inclined edges;
• the insert substantially fills the recess;
• the insert comprises a pair of pads which are positioned so as to be underneath the cheeks of the posterior of a person sitting on the seat portion, and a pair of legs which are positioned so as to be underneath the thighs of the person sitting on the insert;
• the insert is a one piece insert;
• the pads and legs having complementary downwardly facing inclined edges that engage with the upwardly facing inclined edges of the recess;
• and the insert has an upper surface which is flush with the upper surface of the first part.