I would have thought that the ball is in the claimant's court. If they want to sue, then they will presumably take legal advice and act accordingly. If there had been a complaint to the Ombudsman then they could have suggested a compensation award if they decided that maladministration causing loss to the customer had occurred. Maybe the claimant can still make an Ombudsman complaint?
Maybe run it past your legal department but I don't see that there is anything you have to do at this stage. It's down to the claimant to make the next move.
