Another option which you could consider would be to ask the buyer to keep the set and have him resell it.

I sell alot of sliver plated teapot/coffee pot sets and can say that they sell fairly well. I think this buyer got a great deal for $45.00, especially because it includes the tray.  I think if he was to resell he could fetch alot more and save on posting the item back. You have indicated the set has rarely (if ever) been used, so posting more photos in good light, showing the Ranleigh label on the base and photos of the inside condition of the set will all assist with reselling this item.

Even if he returns the set, I think there is a potential for you to be able to sell this set a second time round for more than $45.00.

Don't understand why there would be a problem with it, as it looks like a lovely set in excellent condition. Will be interesting to see what his response will be.  He must have just simply changed his mind.

Good luck, hope you are able to get a good outcome. 🙂