yes. it is valid notice. Opponent's signature is not necessary.
The service of notice to on the lawyer of a party is not ordinarily valid, unless, of course, such lawyer has been duly authorised by the party to represent him by executing a proper vakalatnama.
its no neeed an case laws madam..
if once an advocate entered in to proceedings on behalf of his client mean then no need the client's signature. its could be treated that with in the knowledge of the client.
Dear Abhilasha
See in the para of Vakalatnama.
If lawyers can do wrong then party has to complaint in Bar council
with reg
sreenu