Just found this, it says RAF civilian workers badge 49: RAF trade and misch badges @ Militarybadgecollection.com but doesn't give the size.
Last two photos in the 4th row.
Can't find a specific date for the badge, but it could be this
I don't think that is writing on the lid.... I think its a striker, i.e. it was a Vesta case before conversion.
My greatest fear is that one day I will die and my wife will sell my guns for what I told her I paid for them
"Don't tell me these are investments if you never intend to sell anything" (Quote: Wife)