"Do hope SIL and BIL are registered with a different GP, for starters. You really don't want their medical records being confused. Then there are school records, as they get older National Insurance and tax, even court records if they ever have the misfortune to get a speeding ticket... so many opportunities for confusion."
Ok, some of you are not only being unreasonable, you're being downright irrational at this point.
The GP, the taxman, and any other official authority will never get these two girls confused, because they as standard ask for the date of birth to confirm identity. The girls may be of similar age, but they do not share a date of birth, right?
The reason the authorities do this is that it is not that unusual for two people to share the exact same name, not just a very similar name, in this country. (Just think, what do all the Smiths and Joneses do!?!?!?)
And while Isabella Eve is a lovely name, it is also (this year) an extremely common one. This is the risk you take when you pick two names off the top 10. In fact my cousin had a little one about 9 months ago and named hers Isabella Eve as well. (I did just confirm Eve was in the fact the middle name before posting this as I wasn't sure - which leads to my second point is that most people don't often use their middle names on an everyday basis anyway).
I'd also like to remind those advocating some form of retaliation / mocking that there are CHILDREN INVOLVED in this. Anyone who dares give this second girl a nn to spite the mother is a horrible person, imo. Even if you mock the parents... as this little girl gets older, she'll figure things out, and mocking the parents will be the same as mocking her.
I agree with those advocating an open (and civilised) discussion. As the OP said, she doesn't even know the rationale at this stage!!! They might have a very good reason (or a very bad reason). Yet here we are, all assuming the worst, making plans to start a holy war.
some people need to get a life!!!!!