BlunderBus
A very tempting suggestion, but in my experience from a previous life, although their crime may be "failing to provide regulatory oversight", for a case to prevail you will need to provide a specific example (or examples) of such failure.
Vague accusations will give a half decent lawyer so much room to wiggle and delay and muddy the waters that by the end of the trail, the only winners are the children of said lawyer because he can now put them through top level private schooling.
One avenue is the "judicial review". To do that you'd need to find a situation where they've acted outside their legislative remit. For example if they had (hypothetically speaking) signed off on an operator's FTL scheme which had some non-approved variations from the CAD371 base document..... oh.. wait...