I need help with a toilet issue! I am lucky to have an ancient high-up, pull chain cast iron cistern in my flat. Unfortunately we found today that the 'flush valve' needs replaced. Apparently we have a 'st mungo flush valve'. The plumber who is looking it at it is thankfully one of the few plumbers left who know these systems but he's not confident it will be easy to track down the part. So I'm looking for any suggestions for scrap/reclamation yards where I can look if necessary.