A method of assembling a reinforcement web for use with a wind turbine blade, the method comprising: arranging one or more first laminate layers on a primary surface of a mould, the primary surface terminating at a shoulder portion of the mould defining a mould end surface transverse to the primary surface; arranging a pre-formed flange structure, which comprises a flange portion and a projecting portion oriented transverse to the flange portion, onto the mould with the projecting portion overlapping a portion of the first laminate layers and the flange portion extending along the mould end surface; integrating the first laminate layers and the flange structure by vacuum bag resin injection molding of matrix material and by curing to bond the projecting portion of the flange structure to the first laminate layers and thereby form the reinforcement web; and after arranging the flange structure, clamping the flange structure in position with a locating clamp, characterized in that the locating clamp has first and second clamp blocks (80, 82) and is connected to the mould end surface, the clamping further including moving the first clamp block into removable engagement with the second clamp block to push a clamping surface of the first clamp block against the flange portion to hold the flange structure in position on the mould end surface, wherein clamping the flange structure in position with the locating clamp further comprises: engaging a first abutment surface defined on the first clamp block with a second abutment surface on the second clamp block, the first and second abutment surfaces (102, 90) being oblique to the mould end surface, the engaging of the first and second abutment surfaces (102, 90) forming an interlocked geometry preventing movement of the first clamp block in a direction transverse to the primary surface of the mould. arranging one or more first laminate layers on a primary surface of a mould, the primary surface terminating at a shoulder portion of the mould defining a mould end surface transverse to the primary surface; arranging a pre-formed flange structure, which comprises a flange portion and a projecting portion oriented transverse to the flange portion, onto the mould with the projecting portion overlapping a portion of the first laminate layers and the flange portion extending along the mould end surface; integrating the first laminate layers and the flange structure by vacuum bag resin injection molding of matrix material and by curing to bond the projecting portion of the flange structure to the first laminate layers and thereby form the reinforcement web; and after arranging the flange structure, clamping the flange structure in position with a locating clamp, characterized in that the locating clamp has first and second clamp blocks (80, 82) and is connected to the mould end surface, the clamping further including moving the first clamp block into removable engagement with the second clamp block to push a clamping surface of the first clamp block against the flange portion to hold the flange structure in position on the mould end surface, wherein clamping the flange structure in position with the locating clamp further comprises: engaging a first abutment surface defined on the first clamp block with a second abutment surface on the second clamp block, the first and second abutment surfaces (102, 90) being oblique to the mould end surface, the engaging of the first and second abutment surfaces (102, 90) forming an interlocked geometry preventing movement of the first clamp block in a direction transverse to the primary surface of the mould.