Here are the additional gauge figures that you might find useful (these are not stated in the magazine):
1) 22.5-23 sts and 25 rows to 10 cm on chart A (this is the cable panel on the body) using 5 mm needle.
2) 26 sts and 27.5 rows to 10 cm on chart B (which is the honeycomb pattern for the collar) using 5 mm needle.
I think people knit cables with different tension. So hopefully above above helps. :)
Any questions, please contact me.