A component comprising a first concentric element and a second concentric element in which the first and second concentric elements are positioned relative to each other in the positions in which they are to be bonded together, the first concentric element comprises a first bonding portion with a first bonding face, the second concentric element comprises a second bonding portion with a second bonding face, a first passage, and a second passage, the second bonding portion partially surrounds the first bonding portion and the first and second bonding faces (50, 60) face each other, the first and second bonding faces (50, 60) comprise a first and second void face (56, 61) respectively, collectively the first and second bonding faces (50, 60) comprise an alpha plug having an alpha plug face, a beta plug having a beta plug face, an alpha bearing face, and a beta bearing face, in which the alpha plug face is in sliding contact with the alpha bearing face and the beta plug face is in sliding contact with the beta baring face, the alpha plug is integral with one of the first or second void faces (56, 61) and the alpha bearing face is integral with the other of the first or second void faces (56, 61), the beta plug is integral with one of the first or second void faces (56, 61) and the beta bearing face is integral with the other of the first or second void faces (56, 61), and the alpha and beta plugs (52, 54) and first and second void faces (56, 61) collectively define a void, the first and second passages (62, 64) each extend through the second concentric element from a mouth which opens onto the void to a mouth in an accessible surface of the second concentric element; characterised by the component further comprising an adhesive guide means, in which the adhesive guide means is a fin extending from one of the first and second void faces (74, 83) toward the other of the first and second void faces (74, 83), and the fin has a first end at or adjacent the alpha plug, a second end at or adjacent the beta plug, and the fin extends between its first and second ends in an at least partially non-linear direction, and the fin defines a path between the mouth of the first passage onto the void and the mouth of the second passage onto the void. the first and second concentric elements are positioned relative to each other in the positions in which they are to be bonded together, the first concentric element comprises a first bonding portion with a first bonding face, the second concentric element comprises a second bonding portion with a second bonding face, a first passage, and a second passage, the second bonding portion partially surrounds the first bonding portion and the first and second bonding faces (50, 60) face each other, the first and second bonding faces (50, 60) comprise a first and second void face (56, 61) respectively, collectively the first and second bonding faces (50, 60) comprise an alpha plug having an alpha plug face, a beta plug having a beta plug face, an alpha bearing face, and a beta bearing face, in which the alpha plug face is in sliding contact with the alpha bearing face and the beta plug face is in sliding contact with the beta baring face, the alpha plug is integral with one of the first or second void faces (56, 61) and the alpha bearing face is integral with the other of the first or second void faces (56, 61), the beta plug is integral with one of the first or second void faces (56, 61) and the beta bearing face is integral with the other of the first or second void faces (56, 61), and the alpha and beta plugs (52, 54) and first and second void faces (56, 61) collectively define a void, the alpha plug face is in sliding contact with the alpha bearing face and the beta plug face is in sliding contact with the beta baring face, the alpha plug is integral with one of the first or second void faces (56, 61) and the alpha bearing face is integral with the other of the first or second void faces (56, 61), the beta plug is integral with one of the first or second void faces (56, 61) and the beta bearing face is integral with the other of the first or second void faces (56, 61), and the alpha and beta plugs (52, 54) and first and second void faces (56, 61) collectively define a void, the first and second passages (62, 64) each extend through the second concentric element from a mouth which opens onto the void to a mouth in an accessible surface of the second concentric element; characterised by the component further comprising an adhesive guide means, in which the adhesive guide means is a fin extending from one of the first and second void faces (74, 83) toward the other of the first and second void faces (74, 83), and the fin has a first end at or adjacent the alpha plug, a second end at or adjacent the beta plug, and the fin extends between its first and second ends in an at least partially non-linear direction, and the fin defines a path between the mouth of the first passage onto the void and the mouth of the second passage onto the void.