Hi I have a problem with my flexible pipes on my sink. They need replacing but we are going on holiday so won't be able to get this done till we get back. Is it safe to leave isolation valve turned off on flexible pipe connected taps for a longer period as it will be 2 weeks? Will it cause any issues or are they only supposed to be switched off for very short periods. Sorry if it's a silly question but I am a bit of a novice with plumbing.