the invitation is from friends who we socialise with, but only in a group, so I don't know them all that well really. I have never even met their son.
We seem to be invited to the morning service as well as the evening reception. There are many reasons why I am not keen to go to the service.
Would it seem very rude to say we would love to attend in the evening but can't come to the service? Are they completely separate parts of the event? I am assuming it is not quite like a wedding where the couple may be rather put out if they bother to invite you to the service and you say you are only coming to the reception.
Also, as to presents - I have done a few searches and understand that a grown-up present is in order, but as we don't know this lad at all, would vouchers be OK? The parents are pretty laid back people.