I've not seen that report before. But I've read its summary document just now.
I don't think its conclusions support a claim that there was corruption on a large scale.
The bit that specifically mentions government ministers passing on leads says:
There may have been (and probably was) some level of corruption but I've not seen convincing evidence of what scale it was at.
Okay, so billions of pounds siphoned off to the Tories' mates is fine by you. That's all we needed to know.