Flexi's are fairly common for going as said any decent exhaust place will replace it for you,i am not talkingabout your local exhaust and tyre centre through, more like a powerflow or custom exhuast place.The SC lads get through flexi pipes all the time
https://z22se.co.uk/threads/oh-dear-flexi-blowing.21169/#post-1187715
Just had a quick look and there is a Custom Performance Ltd which may not be million miles away from you.
Also you sure it's not the sensor rather than the cat?