Maydayredalert
It's not a remark. This matters as people think they are getting a remark and that's not what a review of marking is. They are two different things.
The board made it very clear to centres and it says this on the page you've linked to:
If you request a review or priority review of marking:
it includes a clerical re-check
a second examiner will review the paper/recording again to identify genuine marking errors or unreasonable marking
we'll make sure all the marks are counted
Genuine marking errors is where, for example, an examiner has misread an answer, not awarded marks for units when units were present, has an English response been capped as a rubric infringement incorrectly etc.
Unreasonable marking is about whether the mark scheme has been applied fairly, not whether a second marker agrees on the exact mark.
E.g. if first marker put the question in band 3, but the bottom of band 3, the second marker is checking whether the marking was unreasonable (aka is it in the wrong band), not that in their personal opinion they'd go 2 marks higher in band 3. If the second marker thinks the mark scheme has been unreasonably applied then they may move it to band 2 or band 4.
A review and a remark are not the same thing