I installed a shower a few months back. The shower consisted of a thermostatic bar with an outlet at the top with a diverter valve for an overhead rain shower or handheld flexible cord shower head. After a few weeks the overhead shower started dripping, getting worse and worse, until in the end I would set the diverter valve to handheld shower and leave it in the bottom of the tray to drip quietly. It would also stop dripping if I tightened the shower on/off control (more than usual). I have changed cartridges before to stop leaks, but they are so expensive I thought I would save time and buy a new thermostatic shower bar. Having installed the new bar, the thing is still dripping. I cannot fathom out what must be wrong as surely the bar controls the flow of water and that has been replaced. Anyone have any suggestions please?