BBB Own Make Dating?

[SBC]

Here's a BBB "Own Make" I just picked up --



I'm curious whether there's a way of dating this?

On one side of the shank is a diamond, and inside that diamond are three "B"s.
To the left hand side of the diamond is "Own," and to the right hand side is "Make."

On the other side of the shank is the number "130."
Right below the "130" it says "MADE IN LONDON ENGLAND" ("England" is below "Made in London").

The band is badly tarnished (for now), as you can see, but I can make out "STERLING..."

What does the "130" mean? Is that their designation for the shape?

Is there any way of dating this? I know BBB has been around awhile...

 

[OzPiper]

Your best bet is to clean up the silver band and look for hallmarks - in particular a date letter.

One problem - silver designated for export were not required to be hallmarked.

 

[SBC]

Your best bet is to clean up the silver band and look for hallmarks - in particular a date letter.

One problem - silver designated for export were not required to be hallmarked.

I cleaned up the silver with toothpaste (which by the way worked very well) -- and, unfortunately, it turns out that there is nothing else there. Just "STERLING."
Oh well...