When downloading a list of variation items from WooCommerce, in order for all of the items to appear in the mapping screen in Linnworks, the following criteria must be met:

1. The parent SKU must not match any of the child SKU

2. All variation child items must have a SKU assigned to them

3. At least one variation child item must be present within the variation group altogether

In addition to this, the Product.Type attribute of the Parent Item on WooCommerce must be set to Variable

Simple single item products must meet the following criteria:

1. The product type must not be set to Grouped and the Downloadable and Virtual product attributes must both be set to False

2. The product type must be set to Simple and the product must have a SKU