Importing large catalogue of products Wordpress Woocommerce

We require to import approx 6000 products into a Wordpress woocommerce installation. I have all product data in a CSV file and the Woocommerce Product CSV Import Suite. However... of the 6000 products many are duplicates with different category and will need to be filed as appropriate. Also, the CSV importer does cater for the creation of categories as products are imported but not category images, there are approx 1000 categories based on parent, child and grandchild categories. Links to the images are in the CSV file but these will have to be imported separately. Currently when trying to import all products at once, the website crashes (white screen of death), this will also have to be solved. Smaller CSV files work fine. Previous experience with Woocommerce and the Woocommerce Product CSV Import Suite preferable. Also to note, minor formatting of product descriptions may be required. The product catalogue has been imported from wholesaler. Any reference to boxed quantities or bulk discount to be removed. if exists in product description.