Did not get a deal - there wasn't one there to be had - but did manage to ensure that a difficult set of issues was thoroughly explored, that nobody was bullied or abused, and that everyone is clear what the next steps are - and that felt like a win in the circumstances!
Used the Harvard Principled Negotiating approach (see Getting to Yes, Fisheer & Ury) and as ever it delivered a fair, efficient and (reasonably) amicable process, enabling us to clarify that there was no deal that was going to work in a way that avoided the parties attacking each other (again) and demonstrated that the PC had done all it could to facilitate discussions.