It took a while but try
JAR 25 amendment 13.
There's a lot of other info about JAR-FCL 1 and other wonderful stuff guaranteed to have you asleep within seconds.
I've just read some of that and you'll be asleep in a nanosecond.
I've tried searching for the list of JAR 25 and JAR 23 aircraft but I can't find it easily.
Any way,
Here's a simple definition between the two that should guide you.
JAR—23:- Normal, Utility, Aerobatic and Commuter Category Aeroplanes
Airworthiness standards for the certification of aeroplanes in the normal, utility and aerobatic categories that have a seating configuration, excluding pilot seats, of nine or less and a maximum certificated take-off weight of 12 500 lbs or less (5700kg); and propeller-driven twin-engined aeroplanes in the commuter category that have a seating configuration, excluding pilot seats, of nineteen or less and a maximum certificated take-off weight of 19 000 lbs or less.
Eg, Twin Otter, Bandeirante, King Air, Metro
JAR—25:- Large Aeroplanes
Airworthiness standards for the certification of multi engine turbine-powered aeroplanes with a maximum take-off weight greater than 5700 kg.
Eg, Shorts 330, Dash 8 (any of them), B737, Bae 800