Question

Why did Davenport disappear right after the jewellery hold-up? What might his plans have been if, Nolan had not died?

Answer 1

While the police were actively looking into the robbery, Davenport vanished to avoid being discovered and to keep a low profile. If Nolan had survived, Davenport probably intended to meet him later, retrieve the stolen jewellery using the coded message, and then divide the spoils after the search had subsided.