I had a long session with Deep Seek V3 AI and using its knowledge of
invariants of elliptic curves and the j-invariant, I was able to work
out how to move from the minimal model coefficients for the elliptic
curve, to the single parameter generating that curve. It involved the
use of nfroots(,poly) for up to 24 degree polynomials.
So I have gotten working GP Pari code to do this now.