Any ideas / advice ? Yes - keep seeing your mediator (and if you don''t like what he is or isn''t doing, switch to another), be open minded, listen to the other side''s point of view, and be prepared to compromise - and insist that the other side does the same.
Whilst the answers to the questions above would help to fill in some of the information gaps, there are other factors that would need to be taken into account.
It is impossible to give advice that is actually useful unless one knows the whole picture and both sides'' views. To base settlement advice on partial information, which no doubt is well meant, can be misleading and give you unrealistic expectations.