We will
I've received the following from my better-informed friend.
... 'mwarchad' is probably 'gwarchod' which means; 'to guard', and the phrase 'Sidwas wniethus hydwyl' as far as I and my helpers can work out, means: something like:' a slick, mendacious smiling young man.' So the
idea of Judas is in there, somewhere. (I didn't mention that to my friend so as not to skew the result.)
She adds:
I note from looking at my Penguin and Oxford books of Welsh verse that her work is not included.!!! This lady was extremely sceptical about the other sex it seems.