A carbon-loaded polyethylene film was modified through a combination of laser ablation and electrochemical anodisation to yield a mechanically flexible yet electroanalytically sensitive mesh. A custom flavin derivative bearing a pendant phenol substituent was electropolymerised onto the substrate, and its electrochemical properties were investigated. The reversible flavin electrochemistry was retained (Ep = -0.374 V vs. Ag/AgCl, pH 7), and the peak position was found to shift by 60 mV/pH over a range covering pH 2.55 to pH 8.12. The stability of the resulting composite has been evaluated, and the analytical applicability towards the voltammetric measurement of pH in human urine was critically assessed.