Can you be specific about what is actually happening here. Is it the following?
1) You went through the FSPO mediation which did not reach a settlement
2) The FSPO conducted an investigation and asked the bank questions.
3) The bank answered those questions and the FSPO sent you the answers
4) This went back and forward a few times until you both said you had nothing further to say.
5) Now the investigation is finished and the FSPO will, in its own good time, issue a preliminary decision.
6) The bank has contacted the FSPO and said that they would like to engage directly with you, via an independent mediator, and not the FSPO, to see can they reach a settlement.
Brendan