When you said 'called-in' I assumed you meant called in by the SofS.
So, your ward councillor has asked for the planning application to be decided by the LA planning committee, rather than let the Planning Officer make the decision as normal.
In which case your parish council can nominate a councillor to speak at the meeting (probably restricted to about 3 mins of talking) and make any objections you may have. Having several members of your council in the public gallery will support your nominated councillor, as well as your Ward Councillor and helps show your strength of feeling.
However, the vote will often swing on the deciding vote of the chairman, not to mention that if the case planning officer gives his opinion that there are no valid planning objections and that she/he was minded to pass the application, then the District Council may find that the developer will appeal if it is refused, which of course costs money.
The developer will no doubt field their own team at the planning meeting, and will certainly want to use their 3 minutes (or whatever time your LA allows) of public speaking time.
Members of the public can also apply to speak at the meeting, so it may well be worth encouraging that notion, without telling them what to say of course.