My sister was at Manchester University in the early '60s when she came home for summer holidays with her guitar and this version (from memory, with a gap or two)

Oh come, gentle maiden, let me be your lover;
Condemn me no longer to mourn and to weep,
Shot down like a hart in my earnest endeavour.
Come, lower your drawbridge, I'll enter your gate.

(Enter your gate, nonny nonny,
enter your gate, nonny nonny,
lower your drawbridge, I'll enter your gate)

I fear, gentle (??), that I am no maiden,
I'm married to Sir Cedric, the cunning old celt,
And he's gone to the wars for a twelvemonth or longer,
And taken the key to my chastity belt.

(Chastity belt, nonny nonny...)

Fear not, gentle madam, for I know a locksmith.
To his forge we will go, on his door we will knock,
And we will make use of his technical knowledge,
To see if he's able to unpick your lock.

"I fear, Sir and Madam, that I am unable;
My technical knowledge is of no avail.
I can't find the secret to this combination:
The cunning old bastard has fitted a Yale."

"I'm back from the wars with sad news of disaster;
A dreadful misfortune I have to confide:
As my ship was passing the straits of Gibraltar
I carelessly dropped your key over the side"

"Alas and alack, I am locked up forever!"
Then up steps the pageboy, saying "Leave it to me.
If you will allow me to enter your chamber,
I'll undo your lock with my duplicate key."