As I am that person Anja, I can answer definitively, and agree with Lazigirl!
The basic minimum for State Registered Nurse training was 5 'O'levels (or equivalent Scottish Highers). There were a few ways round this:
The General Nursing Council (as it was then) held 'open exams' for those who didn't have the correct qualifications. My s-i-l got in this way.
Hospitals who took on cadet nurses at 16 would train them to sit this exam - one of the nurses who influenced me to become a nurse took this route.
Most hospitals accepted this, but a few major ones didn't.
Another way around was to do the State Enrolled Nursing course mentioned by Lazigirl. It was a 2 year course, and you could then apply to do a 2 year 'conversion' to SRN. I knew quite a lot who did this, but some, from abroad, felt cheated because they ended up not being accepted on to the conversion course.
Although it is not what you asked, the late 60s were the beginning of change in the profession - the Briggs report had recommended that nursing become a graduate profession. I think the first 'Nursing Degree' was offered by Manchester in 1968 (but would stand corrected). A number of 'top' hospitals were offering joint courses - a degree in a related subject + SRN training.
As some of us remember, 'grammar school girls' were sometimes discouraged from becoming nurses (a waste of your education)and these new courses were an attempt to bring them in.
And it's definitely not what you asked, but I have never regretted becoming a nurse instead of going and doing a degree (in what? for what?) and I can tell you that I have never been able to tell from the quality of nursing whether someone was a 'minimum entry' or graduate.
I have had the honour to work alongside excellent nurses from all sorts of backgrounds (and OK, a few duds, but that had nothing to do with their entry qualifications either!)
Of course, I smile now, knowing that when I retired I was working at a 'postgraduate degree' level!