The register an official file uses
Every language has a formal written form and an everyday spoken one, and the two are not the same thing. Arabic holds that distance more firmly than most. A certified translation into Arabic in Leicester is written in the formal register, the one used in records and in letters from an office, because that is the Arabic a reader in Oman expects to find on a file.
Why the wrong register reads as careless
Prose that reads well over coffee reads badly on a record. A clerk in Oman holding your English page next to the Arabic is looking for the wording an office itself would use, not a friendly retelling of it. A certified translation in Leicester for Oman is drafted to sit alongside the papers already in that folder, so the tone matches and no sentence stands out as improvised.
The certification Oman accepts
Certification here is a signature, not a stamp bought at a counter. The translator names the record, dates the sheet and puts a name to the Arabic. Consulates and ministries take that form, which is why a certified translation for Oman needs no court to be involved at any point. The credential asked for is a certified Arabic translator, and that is the whole of it on this route.
What it costs and when it lands
Each page is £25, so the total follows the length of the record and nothing else. Standard work is 3–5 business days from a legible scan, and the express route brings it in at 48 hours. An official Arabic translation in Leicester holds to that same rate for a short school record and a long court file alike, so length is the only thing you have to count.