thanks again Bill and Will for your advice,

I thought I'd post my experience today trying this out.

Yes the 'drilldown' option for the CategoryViewer Model does allow us to have filtering options with the "special" attributes such as Manufacturer, Vendor and Type which could be quite useful.

The Categories themselves, which we have created, continue to show products based on a single selection drill-down mode and don't give us a Viewset that would allow us to create a filtering option using check boxes from what I can see e.g.

Toys (first level category):
Ages 0 - 3 (second level category):
Ages 4 - 6 (second level category):
Ages 5- 7 (second level category):

In the example above we weren't able to see how we could have tick/check boxes so users can filter based on Ages 0 -3 & Ages 4 - 6

this is based on what we could see out of the box with this ViewSet. My senior developer says that we could create a custom controller and module for this, but i wondered if "out of the box" with a little tinkering by our front end guys we could create check box options for filtering sub-categories.

I'll keep posting with our progress if we find anything, in the meanwhile if anyone has advice please be sure to let us know :)

Cheers,
Waldo

You could technically do this without any additional development. It would feel like a slight duplication of work though. In addition to the categories you're already using (or in place of them), you could add properties that mimic the categories. This would give you the checkbox behavior you're looking for.