eBay return postage - once a label is provided, do you have to also arrange collection?

As per above.

I have had to action a return request on Fleabay.

I accepted the return and added my own shipping label which was a RM Special Delivery label.

I got a message from the buyer claiming I forgot to book the collection by Royal Mail, this service costs 48p which I said I will pay, but I wonder if that under eBay rules, I have covered my obligations already? I said to the buyer I do not know when they are in/nor do I know any property access requirements.

TIA.