Flexible moulds as external formwork and a novel robotically fabricated reinforcement, Wound FRP (W-FRP), provide the solution for the manufacture of complex structural concrete components being optimised to minimise material use and further reduce the carbon emissions from constructional industry. However, previous research has shown that the non-prismatic geometries and linear-elastic reinforcement could result in very different structural behaviours from the traditional concrete beams and invalidity of the existing codified design approaches. This research proposes revisions to the empirical equation to calculate the tensile force of inclined flexural reinforcement and a design method to predict the shear capacity of the W-FRP reinforced non-prismatic beams based on Modified Compression Field Theory (MCFT). A full-scale test of fabric formed T beam reinforced with W-FRP was conducted to demonstrate the validity of this new design approach. The research in this paper shows that: 1) the invalidity of the codified design approach could be attributed to the empirical calibration with prismatic beams; 2) geometry of the beam and the W-FRP shear reinforcement ratio are the main factors influence the flexural bar force development and 3) the proposed equation for calculating tensile force of flexural reinforcement could accurately predict the force development. This research provides a practical and valid approach for the future design of non-prismatic beams reinforced with W-FRP and addresses technical challenges in the way to minimising material use in concrete structures.