My 1960s Bungalow has been built with the chimney saddle tray below the roof line, hence heavy rain gives a wet ceiling in the upstairs bedroom. How easy is it to put in a new saddlle tray further up the chimney and how far down from the top does it need to be as its a high chimney (2M to flat dormer roof). Its a shared stack so I could only do my side. The other option would be to bend down the tray that there perhaps so water comes all the way down and is spread around?