Conversation starts to echo around Una's French country house (7)
I believe the answer is:
chateau
'french country house' is the definition.
(I've seen this before)
'conversation starts to echo around una's' is the wordplay.
'conversation' becomes 'chat' (chat is a kind of conversation).
'starts to' indicates taking the first letters.
The initial letters of 'echo around una' is 'eau'.
'chat'+'eau'='CHATEAU'
(Other definitions for chateau that I've seen before include "Manor-house in France" , "Loire Valley attraction" , "French castle or manor" , "French palace" , "country house in Bordeaux?" .)