Having trouble with my shower. When we turn it on, it runs cold for about 30 seconds before getting to correct temperature. It then gets very hot and when you turn it on to cold the water stops as if there is no cold feed. On other occasions it goes off completely other than a trickle of water. The make of shower is Aqualisa and was fitted about 8 years ago, and though not used often has ran ok until recently. Any advice appreciated.
