Which route Mali takes
Get the route straight before you plan around it. Mali has not joined the Hague Apostille Convention, so document legalisation for Mali runs through the consular chain rather than the short one. An apostille for Mali would be the quick answer if the country were inside that arrangement; it is not, so a stamp from the Malian mission in the United Kingdom follows the UK stage. That extra desk is exactly why the whole thing takes as long as it does.
The gap in the middle
This route has one long silence in it. Once your copy is posted to Milton Keynes, there is nothing to do and no counter to visit, because the office there works by post only. Many people treat that silence as lost time and then rush the last stage. It is better read as a window: a fixed stretch when the sheet is beyond your reach and every other part of the job is still fully within it.
The work that fits the window is the work that does not need the sheet. Sister documents can be ordered, names and dates on your other papers can be read against each other, and the money for the later stage can be put aside. An apostille from United Kingdom to Mali is one item in a bigger errand, and the rest of that errand does not pause just because one sheet is in a queue.
Where the paper goes
The order rarely changes. Sunderland Registration Service issues certified copies of births, marriages and deaths, so the sheet that travels is a fresh copy and your own certificate stays in the drawer. The FCDO Legalisation Office then compares the signature on that copy against the specimen it keeps and attaches its certificate. The Malian consular stamp comes last, and a bundle without it is not finished however impressive the earlier marks look.
Getting ready for the Malian stage
The last desk is the one you can prepare for hardest during the wait. A mission usually wants a request that names the person concerned, the papers in a single tidy bundle, and the UK stage plainly finished. So an apostille issued in Sunderland for use in Mali is never the end of the story, and the file you hand over should look complete on arrival. Assembling that bundle in advance turns the final leg into a delivery instead of a fresh piece of work.
Cost, and what the clock really costs
Fees are the small part; sequence is the large one. The £45 standard charge per document is fixed, and the £40 next-day tier is open only to registered businesses, so most private senders wait the ordinary time. Because each stage starts when the last one ends, a week lost to an unwritten covering note costs as much as a week lost in the post. Use the quiet middle and the second half of the route stops being the slow half.