Yes Lex, the job was rolling down new felting and tar like one would put on a domestic flat roof. The problem is probably that due to leaks for so many years before that, the structure underneath was getting damaged and weakened.
Motto to Mr Muirhead: You can't polish a turd. The clever bit is to stop it becoming a turd in the first place.
I can imagine one or two people involved in that project hunting for phone directories to stuff down the back of their pants.... MA loves nothing more than a good witch-hunt and blame-allocation process.