Regarding 'The Dog's Bollocks'...
An episode of QI on British television stated that the origin of this phrase has to do with the children's toy- Meccano.
In its early days, it apparently could be bought in boxed sets of two sizes:
Box Deluxe, and Box Standard.
These thus have given us the terms 'The dog's bollocks' (something excellent), and 'bog standard' (something of bland normality).
Is there any solid evidence for this?