Here's an alphabetic list of the answers in case you're stuck:

ANGEL

CANDLE

ELVES

HAMPER

HOLLY

IVY

MAGI

MANGER

PANTO

SANTA

SNOWMAN

TINSEL

If you really need to, you can scroll further down the page to get the full answers.

A hint
 Yes, the answer to 11 Across is what you think it is, but it isn't at all obvious where it should be inserted. If placed correctly, it leads to a very satisfactory solution. Have another go before you scroll down!

ANSWERS

ACROSS

1 TINSEL
Not a single ticket is left in sell-out concert

6 ANGEL
Doctor Strangelove to advise President on nuclear defence

7 PANTO
Cakes with marzipan topping – yummy!

8 HAMPER
Hash, ampersand and other symbols are used in social media

9 MAGI
Cheer up your neighbours – give them a gift this Christmas!

10 CANDLE
The starter's Turkey breast in aspic and lemon sauce

11 IVY
On Dec 25th, will there be power in kitchens in Kyiv? You'd hope so

DOWN

2 SANTA
The weather was very pleasant at first – and then the climate changed!

3 SNOWMAN
Who's now managing Southampton, after Hasenhuttl's departure?

4 ELVES
Twelve seeds at Wimbledon? I thought there were 32!

5 MANGER
PM angers MPs over onshore windfarm ban

8 HOLLY
Man finds print signed by Andy Warhol lying in his attic

Happy Christmas!