I've had a real problem, but have only got 19d and 21ac to go (think 21ac maybe kaput). Also, the ennobling instruction makes no sense - I'd be grateful for any help. Thanks
19d - Works out formula - writer's configuration is not written down (7)
i---t-s
21ac - Ford model Torino cast destroyed...
k---t (think this maybe kaput, if so third letter of 19d is p.
Help needed with the ennobling instructions, which are "change fifth row after twenty four". I can't make any sense of it - what to do and which words need changing.