A combustor for a gas turbine engine, comprising: a support shell having an interior surface and an exterior surface; a combustor liner segment seal member comprising: a center section having a length and a height, and having a base surface, a gas path surface, a forward side surface, and an aft side surface, and a lengthwise extending channel disposed in the base surface wherein the height extends between a base surface and the gas path surface; a forward flange extending outwardly from the forward side surface, the forward flange having a width, a height, a shell side surface, and a liner side surface; and an aft flange extending outwardly from the aft side surface, the aft flange having a width, a height, a shell side surface, and a liner side surface; a forward liner segment; and an aft liner segment, wherein the forward liner segment and the aft liner segment are separated from one another by a gap, and the seal member is disposed within the gap; characterised in that: the support shell comprises a plurality of impingement cooling holes disposed within the shell and extending between the interior surface and the exterior surface; the impingement cooling holes are aligned with the channel; one or more cooling air apertures are disposed in at least one of the forward side surface and the aft side surface, wherein cooling air travels through the impingement cooling holes, into the channel, and cooling air exits the channel through the one or more cooling holes; the forward liner segment is attached to the inner surface of the shell, the forward liner segment having an edge surface extending between a face surface and a back surface, and a seal shoulder; the aft liner segment is attached to the inner surface of the support shell, the aft liner segment having an edge surface extending between a face surface and a back surface, and a seal shoulder; and in that at least some of the plurality of impingement cooling holes are oriented to direct cooling air to impinge on the seal member. a support shell having an interior surface and an exterior surface; a combustor liner segment seal member comprising: a center section having a length and a height, and having a base surface, a gas path surface, a forward side surface, and an aft side surface, and a lengthwise extending channel disposed in the base surface wherein the height extends between a base surface and the gas path surface; a forward flange extending outwardly from the forward side surface, the forward flange having a width, a height, a shell side surface, and a liner side surface; and an aft flange extending outwardly from the aft side surface, the aft flange having a width, a height, a shell side surface, and a liner side surface; a center section having a length and a height, and having a base surface, a gas path surface, a forward side surface, and an aft side surface, and a lengthwise extending channel disposed in the base surface wherein the height extends between a base surface and the gas path surface; a forward flange extending outwardly from the forward side surface, the forward flange having a width, a height, a shell side surface, and a liner side surface; and an aft flange extending outwardly from the aft side surface, the aft flange having a width, a height, a shell side surface, and a liner side surface; a forward liner segment; and an aft liner segment, wherein the forward liner segment and the aft liner segment are separated from one another by a gap, and the seal member is disposed within the gap; characterised in that: the support shell comprises a plurality of impingement cooling holes disposed within the shell and extending between the interior surface and the exterior surface; the impingement cooling holes are aligned with the channel; one or more cooling air apertures are disposed in at least one of the forward side surface and the aft side surface, wherein cooling air travels through the impingement cooling holes, into the channel, and cooling air exits the channel through the one or more cooling holes; the forward liner segment is attached to the inner surface of the shell, the forward liner segment having an edge surface extending between a face surface and a back surface, and a seal shoulder; the aft liner segment is attached to the inner surface of the support shell, the aft liner segment having an edge surface extending between a face surface and a back surface, and a seal shoulder; and in that at least some of the plurality of impingement cooling holes are oriented to direct cooling air to impinge on the seal member. the support shell comprises a plurality of impingement cooling holes disposed within the shell and extending between the interior surface and the exterior surface; the impingement cooling holes are aligned with the channel; one or more cooling air apertures are disposed in at least one of the forward side surface and the aft side surface, wherein cooling air travels through the impingement cooling holes, into the channel, and cooling air exits the channel through the one or more cooling holes; the forward liner segment is attached to the inner surface of the shell, the forward liner segment having an edge surface extending between a face surface and a back surface, and a seal shoulder; the aft liner segment is attached to the inner surface of the support shell, the aft liner segment having an edge surface extending between a face surface and a back surface, and a seal shoulder; and in that at least some of the plurality of impingement cooling holes are oriented to direct cooling air to impinge on the seal member.