Change a CheckMK packaged script - is the local override directory to stop overwrites?

I want to change the default output of check_mk-fortigate_ipsecvpn as it annoyingly doesn’t show the Up VPNs…which is a bit silly. Can i change it to what i want, and if so is there any locaol directory structure that I can copy it to to stop it being overwritten?

you can make your changes in ~/local/share/check_mk/checks. Files in this directory are not overwritten by updates.