I have just had a letter returned from the international Royal Mail hub as "NO PO Box # RTS".

It was sent to Dubai - looking online, I hve found https://www.royalmail.com/sending/international/country-guides/united-arab-emirates

The customer does not have a post office box, just a physical street address.

Surely it would be helpful if this information / warning appeared on Click & Drop - would the post office even know to reject it I wonder?

I could potentially have sent it as a small packet according to that guidance, but not even sure if that would be an option without trying it! Another £9.70 wasted for tracked & signed with no possible means of the letter even getting out of the country!!