Hide post new thread button if forum is a category?

[betts02]

STEP/1
WORKING GROUP FORUMS
Parent Forum - No One
Act as Forum
(Will act as category if no) - NO
Forum is Active
(Will not appear if set to no, but remains accessible if the forum's URL is known) - YES
Forum is Open
(Set this to 'No' to prevent any new posts being made in this forum) - NO

STEP/2
WORKING GROUPS
Parent Forum - WORKING GROUP FORUMS
Act as Forum
(Will act as category if no) - YES
Forum is Active
(Will not appear if set to no, but remains accessible if the forum's URL is known) - YES
Forum is Open
(Set this to 'No' to prevent any new posts being made in this forum) - NO

STEP/3
GENERAL WORKING GROUPS DISCUSSION
Parent Forum - WORKING GROUPS
Act as Forum
(Will act as category if no) - YES
Forum is Active
(Will not appear if set to no, but remains accessible if the forum's URL is known)
Forum is Open
(Set this to 'No' to prevent any new posts being made in this forum)

If that works then repeat step 3 for each sub-forum and let me know mate