At the risk of craven me-tooery, accompanied by multiple hat-tippery, I would just point out that this Number Ten petition about letterboxes ought not to pass without mention of that wonderful song in the Liberator Song book called "Letterboxes", which was written by Chris Young and goes (to the tune of "Little Boxes"),in part:
Letterboxes on the doorfronts,
Letterboxes going snippy-snappy;
Letterboxes on the doorfronts
-Letterboxes hurt and maim.
There's a high one and a low one,
And a small one and a narrow one;
And they all stick or go snipy-snappy,
And they all hurt just the same.
The complete words are here - scroll half way down the page.
Mulitple hat tips to: