What part of the wedding does this look like im invited to?

I have an invite from someone who isnt very close (but shes worked with my partner for years) for their wedding at a banqueting suite. Im not sure what religion they are so i dont know whether they could be having the ceremony at this place. Its 2pm and my partner seems to think were invited to all of it but I dont think we are. Do people sometimes get invited to the meal and not the ceremony or not? Also would i be too overdressed to wear a dress and fascinator or should i dim my outfit down a bit?