We've just installed a new Mira Coda Pro ERD shower as part of our bathroom re-fit. Our oil fed boiler is a Worcester Greenstar. I was worried that the flow rate wouldn't be that good, but it's the opposite. The shower waste is just about coping with the amount of water and I think I need to find a way to reduce the flow rate (the shower itself doesn't allow for that, just lets you choose between the hand held head and the drench head). It's not so bad that it hurts but slightly less would be better and would stop water from pooling in the tray before it drains. I've read elsewhere that a small coin with a hole drilled in it can be fitted between the valve and head to reduce the flow. Is that a safe way to do it? There are isolating valves fitted to the hot and cold supplies at the start of the pipe runs and I thought of closing those slightly, but that would also affect the bath and basin fill rates, when ideally I just want to sort the shower.