Wow. Just read all of the updates, and just wow, that's a lot to get my head around. I'll try and address some of the points.
The groom and his family left pretty much straight away. The not-bride didn't give any details of the conversation and I haven't asked.
The not-bride spoke to every guest who was already at the hotel yesterday and rang everyone else, she has offered to reimburse all travel costs and it was a 'no gift' wedding so that isn't an issue.
The friend in NY is female, so no to the poster who said I had deliberately not divulged the sex and clearly thought they were up to something.
Said friend lives upstate in the middle of nowhere so no the not-bride will not be 'dancing her way around NYC in her designer shoes'
Fortunately they were renting a house short term whilst they looked at somewhere to buy. She has again spoken to the groom this morning and arranged to go round to get some stuff and have a chat about the logistics of everything later today.
The reception didn't go ahead, some of the guests stayed and had lunch again covered by the bride, most went home. I tried to find a charity to give the food to but as it was a Saturday most of the offices were closed so I couldn't and the local hospital wouldn't take the flowers. So the best I could do was the flowers and cake went to a nearby old-people's home.
To the poster who wished fibroids and infertility on her in her 40's, she's 38 and childless by choice, and you really need some help.
Thank you everyone for your advice, some of it was really useful.