Grade II listed cottage ledged front door deadlock.

[ryoc]

I hope someone can help. We have a Grade II listed cottage with a wide plank ledge front door, assembled with rose head cast iron nails through into the ledges. I have purchased a large antique Chubb rim deadlock and a purpose made mortice lock keep, as the door reveal is to deep, and not suitable for a standard rim lock keep.
Is this sufficient for building insurance purposes? I cannot easily fit a 5 lever mortice lock. The door also has a modern Yale cylinder lock fitted. Thanks! - Paul