You can list with free postage, factor that cost into your item price and use your own postage outside of eBay.

To get the buyer's full address and mark dispatched you have to print the original Simple Delivery label.   It will remain unused and you can claim a refund for it here:
https://www.ebay.co.uk/claims/simple-delivery/refund/seller

The payment may be held for 14 days.