One name, one spelling
Every desk on this route is doing the same small thing: matching a paper to a person. That match runs on the name, so a middle name printed on one sheet and dropped from the next is enough to hold up a file. Write your name out once, in the form your passport carries, and hold every later sheet to it. The habit costs nothing now and saves a great deal later.
The mark Yemen actually reads
Yemen has not joined the Hague Apostille Convention. That one fact rewrites the route, because the short cut of a single stamp exists only between countries that both signed it. An apostille from United Kingdom to Yemen therefore ends the British share of the work and nothing beyond it. What makes the file usable is a later mark, added by an official acting for Yemen, and no British office can stand in for it.
What Edinburgh can hand you
Edinburgh Registration Service at City Chambers, 253 High Street, Edinburgh EH1 1YP issues certified extracts of Scottish civil records — births, marriages and deaths. An extract is a signed record rather than a photocopy, and it carries the spelling the Scottish registers hold. Where that spelling differs from your passport, you have found the trouble in week one, which is the cheapest week to find it.
The Arabic half of the bundle
Language is the second place a Yemen file stalls. Arabic runs official life there, so an English extract usually travels with an Arabic one beside it. Getting the name in that Arabic text to match your passport form is the whole reason for settling the spelling first. A translator writes what the page in front of them says, so a wrong sheet simply becomes a faithful copy of the mistake.
Planning a route with an open end
Two of the three stages behave. A fresh extract can be ordered on a known day, and the British charge is published: £45 for each paper by post, £40 on the next-day lane. The consular stage publishes neither a price nor a pace, so put every spare day at that end of the plan. Document legalisation for Yemen breaks on timetables far more often than on paperwork.