[CentOS] Odd issue with custom udev rule at boot

Hi All,

I've written a custom udev rule to change the permissions of /dev/ttyS* but it doesn't seem to be working at boot up. If I run

/sbin/udevcontrol reload_rules; udevtrigger

The rules are parsed, applied and the permissions are then correct but why is it not doing so at boot? The file in questions I've called /etc/udev/rules.d/49-udev-override.rules and it contains

KERNEL=="tty[A-Z]*", NAME="%k", GROUP="rcl", MODE="0660", OPTIONS="last_rule"

the default 50-udev.rules file has been left untouched. SELinux is in permissive mode and so I can't find a reason why it is happening. Anyone have any ideas?