Black tie NYE - What do teen boys need?

[Council]

On something of a whim I've booked a four night break at a nice hotel over New Year.

New Year's Eve is a gala dinner with dancing and fireworks and a "Dress to impress, black tie preferred" dress code. So, black tie not compulsory. DH and I can conform OK but boys aged 14 & 16 will be expensive to kit out properly and will likely never wear it again.

DS1 has a suit he had for is prom, although not black tie, I'm sure that will be fine, but what about DS2? Would you take him in black (school) trousers and a smart shirt or do we need to do better than that? FWIW, neither boy could care less about clothes so don't have strong opinions of what they'd like to wear.

My DSs are 13yo and a very tall 10yo. When they needed something formal this year I bought these runners, nice dark jeans, and a shirt or aertex top.
As long as they are clean, smart and tidy they'll be fine.
You could switch the jeans for chinos?

They have worn all the stuff quite a bit since, so wasn't wasted money.

Where is it? Black tie in U.K. Or Europe will from Tropics...

Yes, in middle England Trailedanderror. Country Hotel.

Thanks Sharon