A face seal assembly for a gas turbine engine, comprising: a seal; and a seal carrier, the seal carrier including: a main plate portion; a cylindrical body extending away from the main plate portion; and a seal retention structure at an end of the cylindrical body distal from the main plate portion, the seal retention structure including: a first seal wall, a second seal wall and a base seal wall, the first seal wall, the second seal wall and the base seal wall defining a groove for receiving the seal therein, the second seal wall extending radially outwardly to a non-uniform radial location; wherein the main plate portion defines anti-rotation slots and provides flanges for attachment of spring fastener features; characterised in that the second seal wall includes a plurality of segments extending to a common, first radial location and a plurality of recessed portions extending to a second radial location that is radially inward of the first radial location; and each of the plurality of recessed portions extends circumferentially between an adjacent pair of the plurality of segments. a seal; and a seal carrier, the seal carrier including: a main plate portion; a cylindrical body extending away from the main plate portion; and a seal retention structure at an end of the cylindrical body distal from the main plate portion, the seal retention structure including: a first seal wall, a second seal wall and a base seal wall, the first seal wall, the second seal wall and the base seal wall defining a groove for receiving the seal therein, the second seal wall extending radially outwardly to a non-uniform radial location; wherein the main plate portion defines anti-rotation slots and provides flanges for attachment of spring fastener features; characterised in that the second seal wall includes a plurality of segments extending to a common, first radial location and a plurality of recessed portions extending to a second radial location that is radially inward of the first radial location; and each of the plurality of recessed portions extends circumferentially between an adjacent pair of the plurality of segments. a main plate portion; a cylindrical body extending away from the main plate portion; and a seal retention structure at an end of the cylindrical body distal from the main plate portion, the seal retention structure including: a first seal wall, a second seal wall and a base seal wall, the first seal wall, the second seal wall and the base seal wall defining a groove for receiving the seal therein, the second seal wall extending radially outwardly to a non-uniform radial location; wherein the main plate portion defines anti-rotation slots and provides flanges for attachment of spring fastener features; characterised in that the second seal wall includes a plurality of segments extending to a common, first radial location and a plurality of recessed portions extending to a second radial location that is radially inward of the first radial location; and each of the plurality of recessed portions extends circumferentially between an adjacent pair of the plurality of segments. a first seal wall, a second seal wall and a base seal wall, the first seal wall, the second seal wall and the base seal wall defining a groove for receiving the seal therein, the second seal wall extending radially outwardly to a non-uniform radial location; wherein the main plate portion defines anti-rotation slots and provides flanges for attachment of spring fastener features; characterised in that the second seal wall includes a plurality of segments extending to a common, first radial location and a plurality of recessed portions extending to a second radial location that is radially inward of the first radial location; and each of the plurality of recessed portions extends circumferentially between an adjacent pair of the plurality of segments.