It's not like you're getting no sleep as even if you go to bed at midnight, you've still got 5 solid hours before the sunlight starts to creep in. So you are being a bit dramatic, really.
Is competitive under-sleeping now a thing on MN?! 
Loving the people saying that if OP can't sleep, because of the missing curtains, OP's DH can take that room and not sleep - problem sorted!
However much you're paying, curtains (or blinds) are a standard essential. It's not like the difference between having Sky vs Freesat; or luxurious sofas vs simple Ikea jobbies. I also don't think £1,000 is cheap at all, depending on the location and size, especially outside of the summer holidays - not extortionate, but not cheap.
We once stayed at a holiday cottage that didn't have any curtains at all in the bathroom - no shower curtain (shower over the bath) and nothing to cover the windows, overlooked by several neighbouring houses. We later discovered that the cottage was actually owned by a celebrity (although we hadn't heard of her at the time), and she had a cleaner/housekeeper; so maybe she thought she was too busy/important to actually bother about providing a good basic standard for guests.
The furniture was horrendously uncomfy as well and the TV/DVD player (advertised as 'satellite', but that was a lie) would only play the one DVD that was in it: 'Rudolph the Red-Nosed Reindeer', freebie given away with the Daily Mail - and we stayed in July!
If you run a holiday let and you leave guests having to make do - cobbling together 'curtains' with bin bags, foil, bed sheets or whatever - then you have spectacularly failed, and you should be ashamed of yourself. People have paid good money for a holiday and should be deciding when to go to the beach or which cafe/shops/attractions to visit; not how to put up with accommodation that's unfit for purpose.