@Jim247. Well, I can't tell you how to "cheat" the system and Airbnb won't likely tell you either as they won't want to compromise their ability to do business in London, the second largest city for Airbnb listings after Paris.
Keep in mind you will need to provide ID, email, phone number for whatever host profile you establish and I'm quite sure Airbnb has methods to detect whenever a user tries to create an "Alias" profile / account. Many users try to do this to escape bad reviews or get around their account being removed by Airbnb.
Also, keep in mind that guests regularly report to Airbnb any host they they feel is not representing thier space honestly. You'd be surprised how many guests report listings where the host does not have permission to rent their space (not your situation, but similar).
If a guest believes that they are renting flat 13 and then are redirected by you to flat 12, you could expect that guests will either comment this on a review or just flag the listing for review by Airbnb's Trust and Safety team.
You might get away with it for some time, but eventually I think that doing this might come back to bite you where it hurts. Once Airbnb detects some kind of subversion, a host's profile is removed for life which may be worse that the London restrictions.
I'm sorry that the authorities in London have this restriction on short term rentals as I'm sure this really puts a crimp in your income.