Have recently had the idea of getting a bunch of friends together (somewhere in the region of 10-20) to stay in a holiday cottage/barn style place for a few nights over New Years.

Anyone done this before and have any recommendations?

Somewhere in England/Wales, not too far north preferably as we’re mostly located down south, and I like the idea of somewhere relatively remote but not too bothered.

And have I left it too late to book this?

Yeah we did it about 10 years ago now, stayed near Malaig with a load of friends and their kids for a week. Was great we set fireworks off at Midnight and the locals loved it.

We also did it 10 yrs ago this yr. there was 9 adults and our 9mnth old. Stayed up near high force waterfall on a remote hillside. Loads of beer/food and my first encounter with a log burner! It snowed like **** new years day and we sledged in the dark 6 up on a huge sheet of polythene we found in one of the outhouses! Good times!!

I have done this with Friends a few times in Wales and the lake district.
The good places will be booked up early so if you’re looking for this year then you may struggle to find anywhere decent for that many people.
We booked places for 2 years in advance but that was the extreme, usually though the early part of the year is the best time to get a good venue sorted. We had similar numbers to you.
You’ll have a great time though. They are always events looked back on with great fondness.

Any more specific recommendations of places to stay?

Googling seems to throw up loads of websites and results, there do seem to be some available at least.