The steps that only run one way
A seal is a one-way step. Once an office has attached its certificate to a sheet, that sheet is finished: the certificate belongs to it alone and cannot be shifted onto a neater copy or a later reprint. Nothing later in the chain repairs an error underneath, which is why care at the start is worth so much more than care at the end.
The same holds for the sheet as an object. Marks, trimming or extra staples added after a stamp turn a clean file into a doubtful one, and no desk will vouch for what it did not attach. Treat a stamped sheet as read-only from that moment and keep it flat until it is handed over.
What you can always redo
The reversible move is the copy itself. Manchester Register Office can issue another certified copy of a civil record whenever you need one, so a spoiled run is a delay and a fee rather than a lost record. Your own certificate never has to enter the chain at all, which keeps the one truly irreplaceable item out of reach of any of this.
Choices about route and timing are also open right up to the moment you commit. What you need for an apostille for Benin is settled knowledge, not something the offices decide case by case, so you can plan the whole chain on paper before spending anything.
Benin and the Convention
An apostille for Benin will not close the file, because Benin has not joined the Hague Apostille Convention. Document legalisation for Benin therefore runs through a consular desk, which adds its own stamp after the British one. That second desk is why the order of steps is so rigid here: each office builds on the sheet the last one handed back.
There is no apostille issued in Manchester for use in Benin available over a counter, and an apostille from United Kingdom to Benin would leave the sheet short of the stamp the far end looks for. Knowing that at the start is what keeps the one-way steps from being taken in the wrong order.
The short list to settle first
Read the names, dates and places on the copy against the record you hold. Decide which country the file is for and keep that decision. Work out how many sealed sheets you will need, since each one runs alone. Settle those three before a fee is paid, and the rest of the route is simply waiting.