If the sofa is sinking, the chances are that something has gone wrong with the frame which is obviously a manufacturers defect. Most suites comes with a 5 year Guarantee anyway, certainly 3 years (without extra insurance), so I can't see why they are stalling. It seems to me that they are just trying to pass the buck.
Send a recorded letter to both the manufacturer and the insurance company explaining that you are unhappy with the messing around and you plan to take the matter up with the Office Of Fair Trading. Chances are they will know you're not messing ( hence the recorded delivery ). They will probably then contact each other until one decides to take responsibility, or even share it.
If that fails, contact the Office Of Fair Trading. A call to one of them from the OFT will normally light that rocket they have sticking out of their backsides.
2 or 3 phone calls or letters a week would be a pain in the backside for you to do, but a bigger pain in the backside for them to deal with. Don't wait for them to reply. Ring them and ask them if they have received your letters. Also monitor every call you make :- Time, date, the persons name whom you spoke to, what they said etc,etc.
Be like a dog with a bone with both of them, they will soon cough up.
If any of this has been any help at all, please be so kind and click the small scales on the left and leave a short comment.
Thank You and Good Luck
