When you hire a company like oracle to create you a business system, they already know that their job is primarily to characterise your existing processes, suggest new ones, document existing ones -- to very high levels of detail. Then the job is to provide an IT system.

They know, very very well, that if they screw up the first part, the second part will be undeliverable. Of course, a local council would not know this.

So the blame is entirely on them. That's the job they bid for. They may be cynically doing a bad job on the first part, convincing the local gov that it's their fault, then exploiting that for more time/money.

This seems highly likely.

A newer tech consultancy might not realise that this is the biz they are in; oracle do. You job is business process consultancy using IT.