Remove chimney or re-support?

Ultranol_2

My partner and I recently purchased into a mid-terrace Victorian house. The rear chimney has been removed (many years ago) on the ground and 1st floor, and is supported in the loft with two RSJs and a metal plate. In our survey, this structure was deemed not up to current buildings standards and possibly and so we put money aside to rectify it. We got a structural engineer round to look at the chimney and he has said:

“While the brickwork appears to be fairly stable in the short term, it remains vulnerable and shows signs of ongoing progressive movement. With further movement it may reach a point at which it becomes unstable and eventually collapses. It is not possible to state with certainty if or when this will happen but steps should be taken now to prevent this.”

The two options he has given us are to demolish the chimney stack or to install a new specially designed steel support.

I was just wondering if anyone has any experience of this particular situation? I’ve read lots of posts about demolishing a chimney completely, but not just demolishing the chimney in the loft and on the roof. Can anyone give me an idea of which would be more disruptive, or give me any thoughts on cost or which option would be better?

And also, I read somewhere about this type of work affecting home insurance - would we need to inform our insurers if we went ahead?

Thanks