I want the landing page for a manufacturer to be able to be filtered by product specifications in the same way as it is for a category.

I copied the code from the categories module into the manufacturers module and modified the code behind and it partially works but it is delivering inconsistent results depending on each manufacturer and the specifications.

The page renders but it defaults to the first spec option. I'm missing a bit of code somewhere but can see where.

Any way I can get this to work