In our review paperwork, several mistakes were made in the clerk's summary.
There have been a few cases in the last 3 years when this has happened. I can't find them immediately, but if you hunt around, you should turn them up.
They referred to disruption during the exam, which didn't happen;
That is really significant because it casts doubt over whether it was your case that was being considered, or whether the Review notes refer in their entirety to your case.
they talked about his father being away for the week up to and the date of the exam when in fact it was me, his Mum, and finally they made an error regarding a key event at the end of August.
These are subsidiary points, depending on what the significant event was, and whether it really had a bearing on the outcome of the 11+. (PM me on that point if you wish to.)
Would this be enough to argue that the review was unfair, in that they clearly hadn't read my submission properly, or do I need to go into more detail?
The errors certainly suggest that your Review was not conducted thoroughly. You will find references on the main Review Sticky to the fact that each Review receives an average of 6 minutes discussion time, and that is borne out in the covering letter that parents receive with the result of the Review. If part of that 6 minutes was dedicated to discussing erroneous "facts", then you certainly could argue that the Review was anything but fair!