Ikea,
I'm planning on doing the same course NAC starting September ish.
I am working on the figure of 40K to cover the course fee and accomodation and any hidden extras that may crop up.
I figure that having a bit extra to cover any thing that crops up will free me up from worrying about the money and let me get on with training stress free ( i hope ).
Hope that helps.
P.S. are you doing just the JAA course or the FAA/JAA one?