Found this thread whilst swotting for my PPL R/T exam.
CAP 413 says "Flight level (number) hundred". My Trevor Thom book says "Flight level one hundred", but other hundreds must be digit-by-digit ("Flight level two zero zero").
I presume my Thom book (2005 edition) is out of date in this respect, but I'd be interested to know if current PPL exam papers are similarly out of date.