Your listing showed up when I searched for "entire home/apt" aaccommodation in London for the 20th of December to the 4th of January for 5 adults.
You may have done this already but one thing to make sure is to have the "instant book" filter off in the search as yours isn't an instant book listing. Airbnb sometimes sets it on by default. They definitely do this if the search dates are in the near future or if there are lots of listings in the search area.
Great to meet you.
I just wanted to check if you have seen @Steve's response here as he was able to find your listing.
We have also recently created a topic on Search here in the CC, sharing some more information around how it works, which I thought might be interesting to you.
Missed the Host Q&A, watch it now here and if you are short of time, you will also find a short overview of the questions answered.
Looking to contact the Support Team, for details...take a look at the Community Help Guides.