Nick,
I'm a little suprised by your remarks re JAR. As far as certification goes, JAR 29 is extremely similar to FAR 29 to the extent that the chapter and paragraph numbers tally. For CAT A certification performance requirements, they are in agreement. The references to climb gradient sound more like the old UK BCARs.
CLASS 1 and 2 though are sub classifications of CAT A, defined in JAR OPS 3 (an Operational document, not certification)sections F,G and H. The essential difference being that Class 2 ops do not require a safe landing in the event of a reject, but a force landing from which the occupants and third parties remain uninjured. Additionally there is no stay up guarantee with Class 2 until a defined point after take-off, normally on reaching Vy or close to it.
The original question though refered to the en-route phase, which is what my original reply responded to (correctly I believe)