Unfortunately for me I had one of the faulty membranes fitted. Dural was a complete nightmare! Whilst they said they would put everything right they did not, I had a meeting with their managing director who verbally abused me in my own home and continued to shout insults at me as he went down my street back to his car. Formal letters of complaint where met with arrogant replies inviting me to sue them! If only I had the money I would have loved to. So in my experience Dural should be avoided at all costs. It's easily the worst company I have ever dealt with.