Thanks Ladyhawk; I did pick that up, but it's always useful to have it confirmed though!
Yes avm, I think that you are probably correct although I don't then understand why it was included in the letter. Perhaps that was an error. Perhaps the person responding to the enquiry decided to search out of interest, and then that piece of paper just got caught up with the letter.
These things do happen, and this seems a more likely scenario than having an 'Ellen' running between two families!
I might apply for the other 2 childrens' birth certificates, in the hope that there might be a little more info.
Beyond that, and another trip to the LMA, I can't think of anything else.
There is only one census where Ellen is there for sure, and that is the 1901C.
I have sometimes wondered whether the birth place is correct, as my grandfather ended up in Colchester and then Felixstowe . I wondered if there was a reason for him to head in that general direction ....
Thank you everyone!