I buy various items for my work through ebay, can I create a purchase order for each item under the supplier name ebay or take full details from paypal receipts?

A purchase order has no financial impact. That is a document you send to a supplier to order something. Purchase orders are completely optional and would seem to have no purpose for an eBay purchase.

Something purchased via eBay by paying through PayPal can be entered with only a payment transaction. PayPal can be set up as a bank account.

Thanks for your reply, so would you advise that any purchases I make for items or parts I should put through as expenses?

Yes, but understand there is no transaction form that allows you to “put through as expenses” anything you purchase. As I wrote before, you will enter a payment. The payment can be posted to an expense account. But it could also be posted to other account types, depending on what it is for.