A stay in place lining for lining a structure of concrete or other curable construction material comprising: a plurality of panels (302A, 302B) connectable in edge to edge relation via complementary connector components (360, 390) on their longitudinal edges to define at least a portion of a perimeter of the lining; wherein each panel comprises (302A, 302B) a first connector component comprising a protrusion on a first longitudinal edge thereof and a second connector component comprising a receptacle on a second longitudinal edge thereof, each edge-to-edge connection comprising the protrusion of the first panel extended into the receptacle of the second panel; the protrusion comprising a generally straight stem extending from a base of the protrusion and a barb (366A, 366B) extending from the stem and toward the base of the protrusion as it extends away from the stem; the receptacle comprising a catch (396A, 396B) extending into the receptacle and positioned to engage the barb (366A, 366B) when the protrusion is extended into the receptacle, the engagement of the barb (366A, 366B) and the catch (396A, 396B) retaining the connector components (360, 390) in a locked configuration; wherein the protrusion extends into the receptacle in a direction generally parallel to transverse edges of the panels, the transverse edges generally orthogonal to the longitudinal edges; wherein for each panel (302A, 302B), the first connector component is offset from a plane of a body of that panel (302A, 302B); characterized in that for each panel (302A, 302B), the first connector component comprises a concavity that opens in a direction that the stem extends from the base of the protrusion and the second connector component comprises a finger shaped to be complementary to the concavity, the finger extending into the concavity and forming a finger lock when the edge-to-edge connection is made; and wherein for each panel, the finger is offset from an exterior plane of the panel (302A, 302B) and the finger is fully engaged in the concavity when the edge-to-edge connection is made. a plurality of panels (302A, 302B) connectable in edge to edge relation via complementary connector components (360, 390) on their longitudinal edges to define at least a portion of a perimeter of the lining; wherein each panel comprises (302A, 302B) a first connector component comprising a protrusion on a first longitudinal edge thereof and a second connector component comprising a receptacle on a second longitudinal edge thereof, each edge-to-edge connection comprising the protrusion of the first panel extended into the receptacle of the second panel; the protrusion comprising a generally straight stem extending from a base of the protrusion and a barb (366A, 366B) extending from the stem and toward the base of the protrusion as it extends away from the stem; the receptacle comprising a catch (396A, 396B) extending into the receptacle and positioned to engage the barb (366A, 366B) when the protrusion is extended into the receptacle, the engagement of the barb (366A, 366B) and the catch (396A, 396B) retaining the connector components (360, 390) in a locked configuration; wherein the protrusion extends into the receptacle in a direction generally parallel to transverse edges of the panels, the transverse edges generally orthogonal to the longitudinal edges; wherein for each panel (302A, 302B), the first connector component is offset from a plane of a body of that panel (302A, 302B); characterized in that for each panel (302A, 302B), the first connector component comprises a concavity that opens in a direction that the stem extends from the base of the protrusion and the second connector component comprises a finger shaped to be complementary to the concavity, the finger extending into the concavity and forming a finger lock when the edge-to-edge connection is made; and wherein for each panel, the finger is offset from an exterior plane of the panel (302A, 302B) and the finger is fully engaged in the concavity when the edge-to-edge connection is made.