Start with the count
The commonest fault is not a wrong word, it is a missing side. A reverse page holding only a seal, a continuation sheet stapled behind the first, an endorsement in a margin: any of these can drop out between your scanner and the finished file. Counting sides against sides takes a minute and settles it before anything else.
Read the two texts across
Put the source sheet beside the new one and work through the fixed points: surname, given names, day, month, year, and any reference number. A certified translation into Arabic in Leeds should let you do this without help, because those items keep their form and sit in the same order on both pages. Anything that will not line up is worth raising.
The sheet that carries the claim
Behind the new text sits a short statement, signed and dated by the translator, saying the two match. That is the part a certified translation for Algeria really rests on, because it names a person who stands behind the wording. If the name, the date or the signature is missing from it, the rest of the bundle is only text, however good the text is.
If something is wrong
Say what you found and where, quoting the line as it appears. The correction is made in the file and signed again, so what you receive the second time is a whole set rather than an amended page. Keep the earlier bundle out of circulation once the new one arrives, so nobody ends up holding two versions of the same record.