Which route applies for Zambia
An apostille is a single certificate that Convention countries accept from each other with nothing further attached. Zambia has not joined the Hague Apostille Convention, so that shortcut is not on offer. Papers heading there need document legalisation for Zambia: the UK certificate, then a consular stamp from the desk that acts for the country. Both marks belong on the sheet before it leaves the country.
The count is the first decision
Most people plan one document and then discover they needed three. It happens because a stamped paper is usually surrendered, not shown: the office that asked for it files it away and keeps it. So the real question is not how many copies you own, but how many separate bodies abroad will end up holding one of them permanently.
An apostille issued in Newcastle upon Tyne for use in Zambia is bound to one physical sheet, so a spare cannot be produced from a finished file. Each extra sheet repeats the whole chain from the beginning. The moment when this is nearly free is at the register office counter, where several certified copies can be printed together.
The Newcastle upon Tyne stages
Newcastle Register Office, at Civic Centre, Barras Bridge, Newcastle upon Tyne NE1 8QH, re-issues civil records as certified copies, which is why your own certificate never has to travel anywhere. Papers from a court, a college or a company begin with the body that signed them, and how many originals that body will issue is the practical limit on your count.
Each sheet then goes to the FCDO Legalisation Office, PO Box 6255, Milton Keynes MK10 1XX, which covers the whole country by post. What you need for an apostille for Zambia is a recognised signature on an unaltered page, repeated once for every sheet you intend to finish. The office treats each one as its own item.
Cost and timing on this route
The UK stage costs £45 per document by standard post, or £40 per document on the next-day service open to registered businesses, so the figure scales with your count. An apostille from the United Kingdom to Zambia then carries the consular charge on top, set by the mission. Sheets that travel together do at least share the waiting, since one envelope moves through each stage at one pace.