What's the difference between a letter-box and an elephant's arse?

I have just returned home from my usual visit to my wonderful, late 17th century Coaching Inn pub here in Bath, and whilst in there, I had a pleasant conversation with a young postman who is a regular like me.

I explained to him that - because of my interest in antique objects, and not always being at home in the morning - I often had cause to visit our local sorting office to pick up parcels which had been almost delivered when I was out. The reason I brought the subject up is because I saw him roaching a red and white card of the sort which the postie shoves through your box to tell you that you have missed a delivery. He says that they make the best roaches.

We then talked about rubber bands, of which I have a vast collection which have been kindly donated to me by postmen over the last few years, left conveniently on the doorstep of our compact but adorable city apartment.

Anyway, conversations being as tangential as they are, I commented about the high proportion of lesbians that seem to work at the Bath depot, and he asked me if I was talking about his kid sister, who works there.

"Oh no," I replied, not knowing his sister from Eve, "All of them EXCEPT your sister."

"As it happens," he said, "My sister IS a lesbian and she works at the Bath sorting office."

On the way home down Walcot Street, I saw the above graffiti on the side of a little Royal mail box that I use quite often, on my way to the car. Nice to know the old instincts are still as sharp as ever.