It is not necessary for the public notice to be signed, but it must state the date, time and location for the meeting. By virtue of Freedom of Information obligations, the public notice must also give details of the business to be decided at the meeting.
The summons to councillors should be signed by the clerk, although many councils now issue the summons by email, so technically the signature is omitted. The summons must state the time, date and location for the meeting, and must also specify in reasonable detail the business to be transacted. Case law indicates that a decision is invalid if the matter was not adequately described in the summons.
Common sense, and probably Freedom of Information obligations, certainly indicate that details should be provided of how to contact the council.