Re: Hmm...
Their comment was that it is currently working nicely, but it's getting difficult to make meaningful changes. What I assume this means is the code is complex, fragile and full of 30 years of hacks and workarounds.
The brief will not be "provide us a new system that does exactly the same as our current system", but "provide us a new system that fits a new, different, simpler process."
Whatever change they wanted to make to the welfare model could probably be done to the current system, but it would cost $xm and you'd still have the current system at the end of it.