Most of this route happens without you
Once a sheet is posted, you are not in charge of it again until it is handed back. That is not a flaw in the system; it is simply how a route built on desks and post works. What it means in practice is that the item you put into the chain should be one you can replace, and the item you cannot replace should never be in it.
Document legalisation for Democratic Republic of the Congo has two outward legs, because a consular desk adds its stamp after the British stage. Each leg is a journey there, a wait on a desk and a journey back. Counting them honestly is the difference between a plan and a hope.
Why the Congo route has a second leg
An apostille for Democratic Republic of the Congo is not the closing certificate, because the Congo has not joined the Hague Apostille Convention. An apostille from United Kingdom to Democratic Republic of the Congo would leave the sheet without the mark the far end looks for. The consular stage exists to supply it, and that stage is what puts your paper on the road a second time.
So there is no apostille issued in Manchester for use in Democratic Republic of the Congo that shortens the journey, and no local counter that could hand one over anyway. Anyone weighing what you need for an apostille for Democratic Republic of the Congo should read the answer as a description of a two-stage chain rather than of a single errand.
Put a replaceable sheet into the chain
Manchester Register Office prints certified copies of the civil records registered in the city. A copy it seals carries the same weight as the entry behind it, which is why it, and not your own certificate, is the sheet that should travel. Ordering one costs a fee and a short wait, and it removes the only genuinely unrecoverable loss on this route.
Papers that are not civil records come from whichever body issued them, and the same rule applies: get a fresh, properly issued sheet rather than committing the copy you rely on. The offices along the way treat every sheet the same, so nothing is gained by risking the better one.
Keeping a thread you can follow
Write down the day the sheet went out, the way it travelled and any reference the carrier gave you. Do the same for the return. It takes a minute and it turns silence into something you can reason about, which matters most on a chain like this one where two separate absences can blur into a single long gap.