Two roads, one starting line
One road ends with a single slip that Convention countries read on sight. The other runs on to a foreign desk for a further stamp. Document legalisation for Guinea takes the longer road, but both roads begin identically, with a sheet somebody signed and an office willing to vouch for that signature.
Where Guinea stands
Guinea has not joined the Hague Apostille Convention. An apostille issued in Derby for use in Guinea is therefore only half the work, and the second half happens at a consular desk. It still matters that the first half is done on the right sheet, because an apostille from United Kingdom to Guinea is what the consular stamp is placed on top of.
Where a stampable sheet comes from
Derby Register Office at Riverside Chambers, Full Street, Derby DE1 3AF holds the entries behind local civil records and prints certified copies from them. Each copy leaves that office already signed, which is what makes it usable. The FCDO Legalisation Office, PO Box 6255, Milton Keynes MK10 1XX, then works from that signature, by post and without any counter to attend.
Charged by the sheet
The British rate is £45 per document by standard post, or £40 per document next-day if the sender is a registered business. Because the unit is the sheet, ordering one spare copy at the start is a cheap decision compared with restarting later. A further official charge lands at the consular stage, and no figure for it belongs here.
Why a picture will not do
A mark of this kind is a statement about a person's signature, made by an office that recognises it. An image on a screen has no signature on it, only the appearance of one, so there is nothing for that office to stand behind. This is why the chain is stubbornly physical, and why the first job in Derby is producing paper rather than files.