Problem setting up auto leveling

[aaron]

Hi
So now my problem is setting up auto levelling.
In Marlin configuration h I have changed the z level offset for the probe and to what I think is correct and changed Z_raise after homing to 50. I have added G29 to the special codes of slic3r and uploaded the firmware again. When I run G29 the machine probes the table nicely but does not move up to Z50 when finished. And when I start a print the hot end is about 2mm above the build table. It is as if the firmware has not changed.
Grateful for any advice
Aaron