Here are lines amended as per the recording. Some are probably just typos, and very small differences, then of course there are the missing words. I give the verse numbers. I hope this is clear.

1) For he is the greatest robber
As you shall quickly hear
There's not been such a robber found
This last six hundred years

2) For ransom he will offer ye
A-twenty tons of gold [the "a-" is just a filler syllable]

3) For such an arrant robber
Myself will ne'er agree

4) She was as well provided for

5) The same am I – says Captain Ward
Why, ashamed I never will be

6) Had I got a letter through
This two weeks past, or three
I would have spared Lord Essex's life
And this pains me grievously

8) But Ward is the King on sea

That's it. As with all Robin's songs, I'm sure it doesn't come from any one traditional source. Good luck with it.