The "Consulate" is the place. The report you're incorrectly referring to is a "Consular" report. Accuracy counts.
The simple fact remains, despite what you said, it's not actually illegal for a US citizen to enter the USA without a passport, children do it all of the time between the US/Canada. It is definitely required when travelling by air though.
Traveling By Land or By Sea
(from Canada, Mexico, or the Caribbean)
For children 15 or younger (or 16-18 years old and travelling with an organized and supervised school, religious, or other youth group):
one of the documents allowed for adults (passport etc) or
a U.S. birth certificate (original, photocopy, or certified copy) -- photo ID is not required or
U.S. consular report of birth abroad or
Certificate of U.S. Naturalization
In fact, an adult can enter without a passport too if they have an Enhanced Driver's License/ID (EDL) (available in MI, NY, VT, WA; also proposed in AZ, CA, TX) or if an adult is on a cruise ship originating and returning to the US, they can legally enter with a birth certificate.
Sorry I got my consular/consulate mixed up though, that makes all the difference and makes the rest of my post redundant. Hopefully it might save the OP some money, or even a trip to London if she already has a consular report of birth.
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