Hello wce
I think that would be right and I correct myself.
For a short period in the late 1970s it appears that
Challenge Corp did use stickers. Note the pride taken in its placement ...

[Linked Image]

The thing is that when Rover acquired SB in 1980,
the Rover 'green' models reverted back to ID plates
but of a poor quality ...

[Linked Image]

Later, when Rover adopted the new 'red' colour, we see
the return of the cheaper sticker...

[Linked Image]


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Jack