Thanks everyone for the help. I think now just to reknit. I don't mind and I know then I'll be a lot happier with it.
The pattern is one by Kathy Calmejane, it was printed in The Killing Handbook for a Sarah Lund style jumper. I got a bit confused because sometimes it kept reading like "When you get to 47cm . . ." rather than "at 100 rows . . ." or whatever.