I am hoping they will replace the tyre when it goes in for the other issues the car has at the end of this month. In the mean time I inflated it to the correct pressure and put an ring inside the valve stem to stop it leaking which worked at first. Today the tyre was flat again down to 10psi, but at no point during my ownership has the TPM ever given a warning that the tyre is losing pressure. Is the system simply broken? If so what could it be? It will be another problem to add the unfortunately increasing list.