Hi
I have to say, in the same way as you believe but have no proof, that Winifred's birth wasn't registered due to her illigitimacy - you also currently have no proof Jane actually did give birth to Winifred or, for example, that WILLIAMS wasn't the name she was registered as. A statement on a Census is not proof of either.
Winfred could as easily have been Jane's 'adopted' child as anything else, and by 'adopted' in that time, I don't mean officially - I mean if the child was passed to her and often in that type of circumstance, the birth mother was a family member of some sort. This scenario, I believe would have been more likely than being illegally unregistered due to her mother being unwed. And in the family, perhaps this wasn't a big scandal anyway , since Janie's sister had at least 2 illigitimate children.
Having said all of that, I do think now, the Winifred WILLIAMS birth reg. Mar Qtr 1911 belongs to a 1mth old wee girl I found on Family Search in the Helston RD area . Which is not to say she's not your Winfred, listed twice........another not-unheard-of occurence in census.
BUT here's the thing! I think you do have consider the Birth Registration for Wilmot W RICHARDS in the March Qtr Helston after all! Wilmot
is a girls name - I just immediately thought it was only a boys name, and it's not
To illustrate, I just found 2 Wilmot girls and an adult, in Cornwall:
https://familysearch.org/pal:/MM9.1.1/X7LR-XLKhttps://familysearch.org/pal:/MM9.1.1/X7G9-9GCWilmot Clarice RICHARDS birth reg. 1905 in Redruth.
What's the bet your lass is Wilmot Winifred? After all, apparently (from your other topic at:
http://www.rootschat.com/forum/index.php/topic,595997.0.html...her cousin May was actually baptised as Amelia, and Amelia's brother Sampson was baptised as Granville!
Cheers
AMBLY