Customer has asked for a new consumer unit. Part P is in hand so this is not an issue. I know this subject has been done to death. I accept upgrading the meter tails and main earth bonding. Customer has took a dislike to the idea of supplementary bonding. Surface 4mm earth wire in fully tiled bathroom, laminate floor up. There argument that upgarding the C.U. is making the job safer and thats all that they want doing. Do the regs actually stipulate that the supplementary bonding has to be done?