Filter by size/colour and by In Stock

[clairemarie]

Joomla! 3.6.2
VirtueMart 3.0.18

I really need to have a filter module that can filter by custom fields: size and colour and also by what is in stock, like this one here:

Please see the Clothing Size filter on left hand side
http://www.chainreactioncycles.com/jackets-run?f=2258


Can this be done using the native VM Custom Fields?

I have been discussing with Break Designs about his Custom Filter Pro - but it will require the Custom Stockable Fields.  And I'd really like to use the native VM custom fields.

Does anyone know of anything out there?

Thanks

[GJC Web Design]

And I'd really like to use the native VM custom fields.

Just to be a bit more clear -- the site is configured with Multi variant children with sizes/colours etc