One of the most common of the more specialist jobs we undertake is the repair and replacement of sash window cords and sash balances.
We recently had a request to replace sash chains. Although sash chain is readily available from architectural iron mongers. Its very rare to find sash windows which use chains instead of normal sash cord. This is because the cost of the chain is about four times that of nylon cord with no additional benefit other than been out of the ordinary.
Unfortunately for our customer only one chain needed replacing and the shortest chain we could purchase was a 50ft reel at a cost of £90.
At least they'll have plenty of chain at hand if any of the other chains need replacing in the near future.