Hey everyone! The pipes in my house have recently started whistling. However, when I turn on the cold water tap at speed it will stop and if I leave the tap on for a few minutes then the sound will stop for 5-10 minutes after I’ve switched it off. It’s not coming from any particular faucet and there is no sounds coming from my bathroom. The sound is mainly in the kitchen and also near my boiler upstairs. I only have electric in the house. I apologise as I don’t know any technical terms and also am a tenant. I also can’t seem to locate the stopcock. I have included a picture of under my sink but I’m not sure if it is because I think that the pressure may be too high as my mixer tap in my kitchen suggests. Could someone please confirm if this is the stop cock. Other than that I have two red round circular knobs which I’m not sure what they are. All you advice would be greatly appreciated! Thank you!