Thats kinda cool, I like the attention to detain they put in, and SW3 being the route number for the bus is really clever, even if I dont like the bus, I think its silly putting it there and makes it look comical.
So Air did have a tag, but now doesn't?
They're not just random. If I remember correctly, they're the actual support numbers that the contractors would have used.
I can't remember- I worked it out when I was there a couple of years ago. I think you get things like L07 which would be left hand supports 7 or perhaps lift support 7. I forget. But their is some reason behind them.