Prose from Dover?

....Pros from Dover

Was this phrase in existence before Elliott Gould said it on M*A*S*H* ? If so, an someone help with it's origin and meaning?

I found a site that claims the phrase is really "prose from dover"!
Here is a paste from the site:

"I think the word may be pronounced "proa". This is another name for a small ship and derives from the malay word "prau". It does not need much imagination to see how a word such as this could be distorted to "prose". As you know, Britain had an interest in this area in the past and many words which make little sense are still used today."

Hmmmm...!

prau
any of various Indonesian boats usually without a deck that are propelled especially by sails or paddles

This same phrase came up before. But I can't remember what was said. I don't think anyone had an answer. I always thought it had something to do with the White Cliffs of Dover during World War II.