A cover sheet to be secured to the tray of a container in use, the cover sheet being substantially rectangular and comprising a first edge, a second edge, a third edge that is opposite the first edge, and a fourth edge that is opposite the second edge, the cover sheet further comprising: a first layer having an upper surface that defines an upper surface of the cover sheet and a lower surface on which an adhesive layer is applied; and a second layer having a lower surface that defines a lower surface of the cover sheet and an upper surface on which a release layer is applied, wherein the release layer is in contact with the adhesive layer; the first layer having a first pre-formed line of separation that extends across a corner of the cover sheet between the first edge and the second edge to define a tab portion of the first layer, wherein a first intermediate point lying along the first pre-formed line of separation divides the first pre-formed line of separation into a first part that extends from the first intermediate point to the first edge, and a second part that extends from the first intermediate point to the second edge; the second layer having a second pre-formed line of separation that extends from the first edge to one of the second edge and the third edge to define a removable strip of the second layer that is adapted to be removed from the adhesive layer to expose the adhesive layer on a securing portion of the first layer for securing the cover sheet to the tray, wherein a second intermediate point lying along the second pre-formed line of separation, and substantially coincident with the first intermediate point, divides the second pre-formed line of separation into a first part that extends from the second intermediate point to the first edge substantially coincident with the first part of the first pre-formed line of separation, and a second part that extends from the second intermediate point towards the third edge substantially parallel with the second edge. a first layer having an upper surface that defines an upper surface of the cover sheet and a lower surface on which an adhesive layer is applied; and a second layer having a lower surface that defines a lower surface of the cover sheet and an upper surface on which a release layer is applied, wherein the release layer is in contact with the adhesive layer; the first layer having a first pre-formed line of separation that extends across a corner of the cover sheet between the first edge and the second edge to define a tab portion of the first layer, wherein a first intermediate point lying along the first pre-formed line of separation divides the first pre-formed line of separation into a first part that extends from the first intermediate point to the first edge, and a second part that extends from the first intermediate point to the second edge; the second layer having a second pre-formed line of separation that extends from the first edge to one of the second edge and the third edge to define a removable strip of the second layer that is adapted to be removed from the adhesive layer to expose the adhesive layer on a securing portion of the first layer for securing the cover sheet to the tray, wherein a second intermediate point lying along the second pre-formed line of separation, and substantially coincident with the first intermediate point, divides the second pre-formed line of separation into a first part that extends from the second intermediate point to the first edge substantially coincident with the first part of the first pre-formed line of separation, and a second part that extends from the second intermediate point towards the third edge substantially parallel with the second edge.