Embassy legalisation for use in the United States
Take the short answer first. The United States accepts a simpler single-step certification, so the consular route does not apply. Embassy legalization for United States from Coventry is not a service to buy, and nothing is added to the file once the British office has signed it off. One certificate closes the job.
That moves the effort somewhere else. With no mission waiting at the end, the only gate is the British one, and it looks at signatures rather than words. Document legalization for United States turns on getting each private sheet properly signed before it goes anywhere near a post box.
What the American side actually receives
An office, court or law firm in the United States receives a sheet carrying a notary's mark and a British certificate. That is the whole of what this side produces. Consular legalization for United States is no part of it, and no embassy or consulate reviews the file at any point along the way.
American recipients often word a request in their own terms and expect the paper to arrive sealed and intact. Those are rules about delivery, not extra British stages, and nothing in this route stops you meeting them. Read the request twice, then treat getting the bundle there safely as a separate piece of work.
The Coventry → United States route step by step
A private paper needs a signature before anything else can happen. A contract, a resolution or a power of attorney is signed in front of a notary or a solicitor, and that mark is what the later stage recognises. Sign every copy you might need at the same sitting, because a second signing means a second appointment.
Civil records take the shorter opening. Coventry Register Office, Cheylesmore Manor House, Manor House Drive, Coventry CV1 2ND, issues fresh certified copies of birth, marriage and death records, and such a copy travels in place of the certificate you keep. From there both kinds of paper follow one road to Milton Keynes.
Cost and timing
Two costs here, not three. A notary charges for the signing, and an official fee applies at the Legalisation Office for every sheet it stamps. That office takes 7–10 business days as standard, or 2–3 business days by express. No consular fee follows, because no consular desk takes any part in this route.
Before the bundle leaves
Check the company name, the signing date and the page order against the deal papers while everything is still in your hands. Legalize documents for United States as one batch where they belong together. Embassy attestation for United States is not a stage anyone will add afterwards, so what leaves Milton Keynes is the finished article.