There is nothing to be approved for
People often stall at the beginning of this errand while they wait for something that never arrives: a decision, a form to be granted, a confirmation that they are entitled to go ahead. No such step exists. A document issued by a British public body can be put into the route by whoever holds it, and no office asks what gives them the right to do so.
That matters more than it sounds, because the delays here are postal and clerical. Days spent waiting for permission that was never coming are simply lost. What you need for an apostille for Turkmenistan is a suitable sheet and a fee, and both of those are within your reach this week rather than next quarter.
What is settled without you
One thing is decided regardless of what you want, and it is the length of the chain. An apostille for Turkmenistan is not the certificate that ends the job, because Turkmenistan has not joined the Hague Apostille Convention. Document legalisation for Turkmenistan runs on through consular offices, adding a desk and a charge after the British stage.
So an apostille from United Kingdom to Turkmenistan is a first stage rather than a finished file, and there is no apostille issued in Manchester for use in Turkmenistan to be picked up locally. None of that is a verdict on you or your paperwork. It is the route that exists, and it applies to everybody the same way.
What you actually need to hold
The test is about the sheet, not the sender. For births, marriages and deaths registered in the city, Manchester Register Office at Heron House, 47 Lloyd Street, Manchester M2 5LE issues certified copies, and that copy is the thing that makes the journey while your own stays at home in the drawer.
The Legalisation Office (Foreign, Commonwealth & Development Office) then works on that copy by post from PO Box 6255, Milton Keynes MK10 1XX and charges £45 for each document by standard post. It has no public counter in Manchester, which is why the whole British stage happens through a letterbox.
The obstacles that are real
Take away the permission that does not exist and two honest obstacles remain. Each document carries its own fee, so a family's folder costs more than a single sheet does. Two desks in sequence also take longer than one, and nobody sending a file can hurry either along. Those are worth planning around; the gate you imagined is not.