GPRM
They're a motorsport preparation company and they're the ones who built and developed the NGTC formula. All of the NGTC chassis are built initially by them and then sent to the teams - the team then fit all the components (car body shell, engine, suspension, etc etc).
The references to their "poor job" is referring to their chassis design and build quality, which is apparently very poor. I've read quite a bit from Thorney's news articles and from "fabricator" (ex-888 staff) from the BTCC.net forums on it.