Excellent... finally got it working with the help of all of your instructions.
Connecting guitar to Kemper, to Monitor OUT to Apogee Jam using guitar cable,
Made sure Monitor OUT was set to "Master Mono" in OUTPUT settings on page one of OUTPUT and also turned up the MONITOR VOLUME on page 2. Now I just adjust the gain on the side of the Apogee Jam to avoid clipping. It sounds great.
@Michael_dk instructions on getting the clean kemper sound in garageband also worked a treat
thanks again @Lugosi @skoczy @Michael_dk a great help and you probably saved me a few £££ on more gear that I don't really need right now.
Cheers