Ihungil ... great response, thank you. To try and answer some of your questions ...

Installation Check: Result says everything is fine.
Default Template: I'm unfortunately not in a position to test this. It's a live running site and don't have the option of flipping over templates to check. We do however have a test site, which still runs a slightly older version of ZC, but has most of the same customisations on it as the live site. It has CEON version 4.0.8, so I think I'll try upgrading it and see if it helps.
Link to store: www.vanax.co.uk
Debuglog: There are some, which I'm trying to work my way through. I don't think any are connected to this, but i'll double check.

In terms of the installation, the hosting company updated ZC to the latest version, and updated the CEON plugin around the same time. My hunch is that something hasn't been installed properly ... I just can't find what it is. Which isn't helped by the install check saying all is OK.

We have customised some quite a bit of functionality on the site, but most of that customisation was done around initial build. The CEON module worked then, up until the upgrade. Both were run around the same time (CEON and Zencart).

It's not just the category sidebox, no. I'm seeing the same behaviour from the product list pages. Other links, such as the header and footer links are hard coded into template.


"There is no CEON Template" ... yeah, sorry, my poor wording. When installing CEON, there are various files within the ZC site template that need modified. I wasn't sure CEON was overriding anything in there, that was perhaps causing it. But your suggestion that it doesn't alter what's passed in zen_href_link pretty much answers that for me.

The install instructions are indeed good. I've installed the module on another site with no issues, and we had it working on this site with no issues as well. Very clear instructions. Unfortunately we had help with the update, and as such I'm not 100% sure where it's gone wrong, barring uninstalling and reinstalling.

DivaVocals ... thanks, kind of. "I personally will not spend any time troubleguessing on anyone's issue". Don't feel you have to input any further. I was merely asking in the hope someone might have experienced something similar. If you didn't want to answer, you shouldn't have. I'm sorry to see such rude aggression so quickly. I didn't answer some of the questions initially because I was still working on the problem to try and provide more concrete findings to my post. Apologies if it wasn't detailed or prompt enough for you first time around. I know these forums can often be filled with people asking questions without having investigated the issue themselves, and no providing information. I go to pains to try and solve issues first, before posting on forums just for that reason ... I know there are a lot of people like you on here, dedicating time free of charge to help. So I don't want to waste that valuable time.

Unfortunate though that I'm spoken to in such a tone so quickly. The contrast between the response of Ihungil and you is significant.