That exactly mirrors the last experience I had with LibreOffice. Those who know me know I am a big advocate for open formats and anti- tool lock-in. When I last used LibreOffice seriously about 3 years ago, I found it was pretty buggy, but my overriding feeling was exactly what Ewan says here: why are these guys trying to make the tool look like Word (Powerpoint, …)? Why not make a well-designed tool that just knows how to interoperate with the same file formats as MS Office (or at least the standardised export formats)?
One thing this illustrates is that being open source doesn’t guarantee common sense in development (witness the KDE/Gnome wars…) - something more is needed. The level of bugs tells me that something is probably missing in terms of clean architecture and componentisation.
I don’t know what the way out of this is - but at some point one would have to ask the question: could an NHS fork of LibreOffice make sense, in order to clean it up? The amount of work to do so might well be too great to contemplate, and perhaps a clean ground up build with bits of LibreOffice plugged in might be possible.
The other way to look at this is for the procurement side to just say to MS (sometime in the future, after having started a move to desktop Linux): make Office work on Linux, stick to our NHS list of standard open file formats, or else we’re done here.