Royal Mail bummer sticker

The Postcrossing card I received today has a honkin' huge Royal Mail sticker plastered across the front, informing me that the sender didn't pay enough postage and, as apparent punishment, my mail was routed the long way. 

And what was on this postcard? I see a teapot and a clock.

The postcard writer — from the tiny village of Strathblane, Stirlingshire, Stirling council area, Scotland — describes what I'm missing: "This postcard shows the writer and illustrator Judith Kerr with cat, Katinka."

Indeed, now I see that cat leg sticking out from underneath the Royal Mail sticker.

Here's a look, from the National Portrait Gallery in London, at what the sticker has obliterated. Katinka doesn't looked terribly pleased about the situation.