Ray, here's the additional info I've gathered.
1. Size and color are only options outside of available accessories for
2. Not all products have color and size options. Currently we have just have an entry in the options table "One Size" or "No Color Options" for products without the options available.
3. Price is determined by size (where the product has sizes available).
4. SKU is unique to particular color and size options. So a chair model X in red has different SKU to the same chair model X in blue.
I'm also wondering whether to have a separate table for accessories or to use the products table. When the visitor pulls up a particular product there will often be accessories that are needed to use the product. Should I create an accessories table similar to the products table, then have a lookup table that relates a product to one or more accessories? Or perhaps I could put the accessories in the products table and have an additional field like "accessory" so I can filter accessories and products.
Your advice much appreciated!