I went to a special needs school until I was 14 so I definitely didn't do the 11+. Did well in my GSCEs & A Levels but kept failing my maths GCSE by 1-2 points. Got into QUB regardless & went on to study MSc. abroad. I work with numbers in my daily job. Exams are not everything. https://twitter.com/bbctheview/status/1347324587617476611
A few yrs I applied for a job at a charity in Belfast that is related to my field of work/study (Criminology) at the time. I was more than qualified. The only reason they didn't interview me was because I didn't have my GCSE maths. In Belgium, this has never held me back.
Education in the UK & Ireland is far too rigid and prioritises assessment against a set criteria rather than the strengths of the child. Never once have I used algebra while managing project sums worth 100,000s Euro.
No-one in Brussels lists their high school qualifications on their CV either. A Romanian friend of mine found it funny that mines were listed for a while. Many professionals in Brussels also get by alright without university qualifications. Experience & skills are more valuable.