I had high hopes for the beautiful, stylish, and poised KST to bring something wonderful to this dull and anticlimactic genre… boo hoo!
Kids are total brats. Total, total brats. As pp said, a great idea would have been gorgeous Granny to take herself off to JL and buy herself something - maybe a cashmere scarf, fabulous perfume, or some other treats for herself.
They could have turned it around like in Motherland when Julia goes out for the evening and is feeling down about being taken advantage of and unappreciated, expected to magic up Christmas for them all. When she gets back home, her family have done everything she was due to do, ie decorated and prepped the dinner and laid the table. They could have done that, both sides could have gone to JL, the stupid permissive parents could have felt guilty and dragged the kids to John Lewis to decorate and lay the kitchen as an apology to their grandmother for rocking up and being nothing but rude. KST meanwhile was in another JL on the other side of town buying herself jazzy presents. They all come back to the house happy and realise what Christmas is all about, The End. Win-win!