Whilst express post is not my preferred method of posting, and the cost of platinum post is outrageous, if a buyer does request something to be sent by express, to keep post charges down I use a regular express satchel.

BUT .. to meet paypal protection requirements I complete the Australia Post lodgement receipt  that is available from Post Offices, and is normally used for proof of registered post, extra cover insurance etc.

On the lodgement receipt I complete all the required details, cross out the platinum next to the express post tick box and stick the tracking label from the parcel onto the receipt.

I always lodge the express post satchel over a Post Office counter and get lodgement receipt stamped and dated, this serves as proof of postage and proof of addressee details.  This meets paypal's requirements.

I have lodged express satchels by this method at three different Post Offices, I have only had one query from a staff member, and I just explained it was for my business records.