Not a medical or other injury compensation claim, but of interest because of the importance of mediations in those matters is an English Court of Appeal decision Berkeley Square Holdings Ltd v Lancer Property Asset Management Ltd [2021] EWCA Civ 551 (on BAILII).
Described in much more detail on the Civil Litigation Brief blog, the Court of Appeal upheld an order directing that certain statements made without prejudice in a mediation were disclosable and could be referred to in a subsequent defence.
As noted at [51], the second exception identified in Unilever plc v The Proctor & Gamble Co [2000] 1 WLR 2436 was:
….directed to the … question as to whether the contract as made is binding on the parties. It will not be binding if it was made without authority (as the claimants allege in this case) or if it is liable to be set aside on well-established legal grounds.
See in particular the comments at [27] – [28].