Postal delivery of tea gets protection (5,4)
I believe the answer is:
chain mail
'protection' is the definition.
(chain mail is a kind of protection)
'postal delivery of tea' is the wordplay.
I cannot quite understand how this works, but
'tea' could be 'chai' (I've seen this before) and 'chai' is located in the answer.
'postal delivery' could be 'mail' (I've seen this in another clue) and 'mail' is found in the answer.
A single letter 'n' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'gets' is the link.
(Other definitions for chain mail that I've seen before include "Cover protecting old soldier" , "defensive link-up" , "circular letters?" , "Armour of small metal links" , "Protective clothing" .)