It will take a while to get the picture approved I'm sure, but what could this be?
It's an approved stamp over what looks like a night sky
For those who don't know what a dingbat is, if the word dash is written over the word snow then it's
Dashing through the snow
We have sung our way through a Wikipedia list of carols trying to find it, but no joy there (well lots of joy with the singing, but not so much finding the answer)