I like wallowing in a deep bath but the only suggestions offered for increasing the depth required blanking the overflow and losing its valuable function. I tried twisting the elbow at the top of the flexible overflow pipe to point about 45deg upward, making the flexible pipe loop up before descending to the trap. This caused the overflow action to fail completely, so I pierced a small hole through the flexible overflow pipe at the top of the loop, to prevent airlock. The overflow action is now fully effective and no water ever emerges from the pierced hole. The arrangement behaves as though the overflow grille had been raised by about 40 mm and the extra bath water depth is a delight. Does this arrangement violate any regulations or codes of practice?