bracket to mount sign on fire extinguiser frame

Catchy title eh ?
So this is a little bracket thing to allow you to affix a sign onto one of those fire extinguisher frames.
Both my frames are 20mm diameter so I assume that is reasonably standard, scale accordingly to make other sizes.
The sign gets glued onto the flat area and the curved bit clips over the tube. It should be quite firm but it has been designed to also allow a jubilee clip to be put around it to hold it firm.
Mk1 was a bit weak so I added a support strut on the back o