Thank you - the first website was very helpful. I don't tend to believe the latter as scenc --> shan seems a bit far off to change the the vowel, drop to consonants, change the s to sh and add an 'n', it really isn't common at all.
I didn't mean
Sian was English, I said
Shan was an anglicized form
Sian, where the English name
John derived the French name
Jeanne, which derived the Welsh name
Sian, which derived the English name
Shan. Complicated...
I will pass on your findings, thanks again,
~SD