UK Landlord Forum / Life

Hello, I recently had tenants move in October 2018 and the cylinder for the hot water system started to leak so they cylinder was replaced and with it all the pipes. March 26th I get a phone call saying it has been leaking which is odd as I sat and watched it being installed so know it's new. March 27th I get a phone call from the engineer telling me someone has capped off the water and diverted it causing the tank to burst. The tenants claim to know nothing about this, however I find that very hard to believe as they live there. I don't want to pay for another cylinder as I already replaced the old one 3mobths ago and it was brand new and should have lasted 20years. The company who installed it are writing me a report with pictures as they were also shocked by what they found having installed it 3months previous.

What are my options?