Oil Leakage from Boiler

Other

I have a property where the boiler leaked oil and the tenant lost about 130 litres. The landlord had to put in an insurance claim for damage to the kitchen from the oil leak. The tenants had to vacate the property for the work to be done. The tenants are now requesting the cost of the oil back which they lost off the Landlord who is claiming the the tenants need to claim off their own insurance even though it was the Landlords boiler which caused the leak in the first place. Who is liable to pay out for this the Landlords Insurance or the Tenants.