Is Ivy a twin or doesn't she exist?

[Bryant]

In 1941 Dec qtr an Ivy Fearn is stated as being born at Ploughley R.D, Oxfordshire, her sister is also born and she is alive and well and also has a middle name of Ivy.

But does Ivy exist?
The GRO has a page number of 2928 for Ivy and 2928a for her sister which is not something I have come across before, does this indicate that an error was made or that she has another sibling who was born at the same time?

Thanks Bryant

[avm228]

The "a" signifies amendment to the registration, so it is likely to be the same child whose name was changed after the birth was first registered.

[Bryant]

Thank you for the reply

Bryant