Hounslow Hilt

[urbanspaceman]

I've started this new thread because we had hijacked the Border Reivers subject considerably.
What I am trying to establish is how did the very distinctive hilt used on Hounslow Hangars (see image) develop?
It seems to appear from nowhere in my experience (limited) and share no resemblance to anything before or after.
Any pointers regarding it's provenance would be much appreciated.