solved my problem

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.