I had an emergency to deal with so I’m only just getting back to looking at this. The site rollout is going to be very delayed unfortunately because of this problem.
In response to Mr Papa’s post # 9:
ls -ltr in the wp-content directory looking at sp-resources gives:
drwxr-xr-x 11 apache apache 4096 Apr 18 23:50 sp-resources (this is the same as all the other directories such as ‘uploads’ and ‘plugins’ in that directory).
ls -ltr in the sp-resources directory looking at forum-themes gives:
drwxr-xr-x 5 apache apache 53 Apr 18 23:51 forum-themes (this is the same as all the other directories such as forum-language and forum-cache in that directory).
Please note as I mentioned in my post prior to Stephens comment I had already completely de-installed and re-installed the plugin (<edit> including making sure all the ‘sf’ tables were deleted from the database). If there is any assistance you can give I would very much appreciate it.
<edit> Note also that I went and dug out an old test site – WP 3.8.1 and SP 5.4.1 – it was fine. I upgraded that site to WP 3.9 – checked the forum (still running SP 5.4.1) it was fine. I upgraded SP 5.4.1 to 5.4.2 using the ‘upgrade’ option for SP, followed the prompts to upgrade the DB etc, and that site ended up with the forum all messed up just like my primary site.