> From: McGrath of Harlow
>
> That's not "court on the lough" - it's "cure it in the Locke"

I don't think so. The Dubliners definitely sing the third verse as ...

We went out there be (by) Castleknock
Says she to me: "Sure! We're caught on the lock!"
Then I knew she was one of the rare old stock
From outside the Zoological Gardens.

... I've always interpreted this as being simply that they've missed the gates closing and been locked into the park overnight. This used to happen, and probably still does, with Greenwich Park in London.