The free version given above is fairly close, but I think the obviously wrong octaves are that way to accomadate a D tin whistle.
So if you're playing a C recorder (as I recall there's a Bb-B below the C) you'd play the first measure an octave lower, as that is what the melody does - jumps up to the G, not down.
For tin whistle you've got a difficult problem - you could use an A whistle, but you'd have to use a half-hole technique to get a C natural out of it.