Martin wrote in
:
Calculus was first year A level maths and not GCE maths in the 1950s.

I've just checked my certificate, a tatty piece of fanfold paper.
I took University of London O-level maths syllabus d in 1972.

The teachers chose that syllabus (presumably not a nor b nor c)
since it contained calculus. The calculus was limited to
integration and differentiation of polynomials excluding 1/x