@ohwhatisinaname I think you should be honest with yourself about the friend who was a no show as well.
Can you elaborate on this part of the story? Because I think it sounds worthy of its very own CF thread.
Did you end up paying for her flight and hotel, or "just" the hotel? (Please tell me you didn't pay for her flight.)
What was the "bad work situation" that prevented her from attending?
Because the only "bad work situation" I can think of that might possibly justify bailing at the last minute and leaving her friend to pick up the bill is that she lost her job a few days before the hen and doesn't know when her next pay cheque will be. If that's the case, she should still offer to pay you back when she can, even if that's a year from now.
If she was forced to cancel her planned trip by her employer for a business related reason, why are you paying those costs and not her employer?
Assuming she has not actually lost her job, whether or not she could afford to spend/lose this money is a completely separate issue from the "bad work situation" which was the reason she gave for dropping out at the last minute.
£1000 is £1000.
It doesn't matter whether you spend £1000 on attending a very expensive hen do, or whether you set fire to twenty £50 notes and dance naked round the flames. It's still £1000 and it still takes you exactly the same amount of time to earn. If you can't afford £1000 for one reason, you can't afford it for the other reason either.
If she really couldn't afford to lose £1000, the reality is that she couldn't afford to go on the hen. And if that is genuinely the case then it sounds like the "bad work situation" is an excuse she has invented to avoid going and let someone else pick up the bill for the hotel room she couldn't afford but was contractually bound to pay for. If that is what she has done, and she really is a close friend of yours, she should have been honest with you and said, "Look, I'm really in the shit. I haven't got £1000 to pay for this hen and I don't know what to do. Is there any chance you could cover me or lend me the money?" Because it would have cost you exactly the same amount if she had come and you had paid for her, and you might have had a nicer time.
If she could afford to spend £1000 on attending the hen do, then she could also afford to lose £1000 on bailing out of the hen do at the last minute. In that case it's irrelevant whether the reason for bailing out at the last minute is because she actually did have a "bad work situation" or just that she didn't feel like going, or for any other reason. And what you are actually saying is that she could afford to spend £1000 on having a nice time, but she can't afford to flush £1000 down the toilet. Well, actually, she can. She just doesn't want to. That's understandable, but why should you waste £1000 of your own money so she doesn't have to waste £1000 of hers?
You do you, OP, but personally I could not be friends with someone who thought it was OK to put me in that situation.
If £4,500 is a significant amount of money to you, which it sounds like it is even if you can technically afford it, then £1000 (or however much you spent covering your no show friend's share) is not a small amount of money either.
You have a husband and children. Think about what you could have spent that money on as a family. A lovely weekend away with your husband in a really swanky hotel to have a break from the daily grind with children and reconnect as a couple. A long weekend at Center Parks with your whole family. A trip to London to see a show and stay overnight in a hotel. A year of swimming lessons or some other extra curricular activity for your kids. £500 in each of your children's bank accounts which can gain compound interest until they want to spend it on driving lessons. £1000 plus tax relief into your pension. A running away fund in case your marriage suddenly goes tits up and you need to leave your husband and get some quick and dirty legal advice.
Unless you are fabulously wealthy, which it doesn't sound like you are, you simply cannot afford to spend these amounts of money on so-called "friends" who treat you badly, instead of on the things and people who do matter.