The route Egypt uses
Start with the fact that decides everything else. Egypt has not joined the Hague Apostille Convention, so a British paper going there requires embassy legalisation rather than the single-stamp route. There is no version of the job where an apostille for Egypt does the work. Once that is settled, the interesting question is not which certificate but how many papers you are putting through the chain.
The unit of work is one sheet
People plan these jobs as a single errand and are surprised twice — once by the bill and once by the calendar. Every desk in the chain works on one paper at a time, because every paper carries a different signature from a different office. Your envelope is a convenience for the postman. Inside it, five sheets are five pieces of work, and one of them can fail while the other four sail through.
Why spares are cheap and reprints are not
A legalised paper is consumed by the body that receives it. Hand it to a university and it lives in the university's file from then on. If an employer in Egypt then wants the same proof, you are back at the beginning with a fresh sheet. Ordering two certified copies at the same time costs one extra fee. Ordering the second one three months later costs the whole chain again, plus the wait.
Where the copies come from
For civil records the source is the register office. Newcastle Register Office at Civic Centre, Barras Bridge, Newcastle upon Tyne NE1 8QH issues certified copies of births, marriages and deaths registered in the city. A fresh copy from there is the sheet that should travel, so the certificate you keep at home never goes into a postbag. Readers looking up what you need for an apostille for Egypt often find that this is the only local errand on the list.
Pricing and timing a pile of papers
Document legalisation for Egypt is quoted and queued per sheet, so the honest way to plan is to multiply. An apostille issued in Newcastle upon Tyne for use in Egypt would follow the same arithmetic if it were the right certificate, and an apostille from United Kingdom to Egypt is priced the same way per document. Count the sheets, multiply, then add slack for the one that comes back needing something.