Nope.  No opt out now.  I am using Chrome on a P.C.

The only option I have is "Simple" Delivery.  

What is worse, there is no option under "Simple Delivery" to send a small package by Royal Mail.  I can send a medium sized packaged by Royal Mail [which costs more] or an incorrectly sized large letter.  But there is no small sized package option.  

Yet again, eBay has released software which doesn't work properly.  Utterly hopeless.