trying to claim on a policy need advice

A question about : trying to claim on a policy need advice

in brief. took policies out with husband in the 80's.
Had 2 children together. Divorced 2000. He moved to Spain 2010. Changed his name by deed poll summer 2011. He died 23/12/2011.
Discovered policy still active and pays out a sum on death.
I have provided Phoenix (previously Pearl) with marriage and divorce papers, children's birth certificates, the death certificate and a photo of tombstone that is the only thing that gives both names.
He was born gavin Andrew John W********* and died Andy James W*****.
I cannot get a copy of deed poll as he never registered it. I have no idea what happened to his passport, his mother arranged for his body to get back from Spain. And she is now also dead.
Phoenix still say they need more information but I don't know what else I can give them. I don't know his NI number nor do I have his passport.
Any ideas on how I progress here

Best answers:

• Who was the executor for the estate?
• there was no-one. his mum kept all his belonging bought over from spain by his girlfriend. I only realised this policy may still be active when sorting out my own paperwork last summer.
• Have contacted Phoenix again, they are now saying they need the contact details for the "girlfriend" in spain. Well how am I supposed to know. Why do they need to know this as his biological children and his only children our children are next of kin. Why are they stalling in this manner?
  I have asked them to explain why they need to contact her and they wont tell me.
  July this has been going on from and I feel no further forward. Phoenix only write to me if I telephone and request a written response.
  Any suggestions as to who I can go to now.