[g_p]

It's worth noting that courts (in the common law system) don't generally play any kind of inquisitive role in cases - there's a presumption that both sides bring legal representation for an adversarial debate where the court is impartial and independent.

Given many of the sub post masters struggled to fund their legal cases (and legal aid is not likely going to stretch to funding the intensity of expert witness work required to discredit a whole system), this also seems to be one of the non technical failings not often talked about.

There's certainly questions about why courts didn't spot issues, but ultimately the common law adversarial system assumes both parties can get equal quality of representation. Unless you have very strong technical knowledge (this site is a non representative sample!) you'd struggle to really shed any light on the bug and get a court to agree with your line of defence.

Ultimately that's what did happen in the group litigation by Bates, about which the TV drama was ultimately created.