It's just a guess Lookout but I'd say anywhere between 1-2:30 (finished by 2:30) - I'm not so certain he used the bike or he may have cycled part of the way and walked the rest.
the devious thing about that is if he had cycled back wearing a hat and scarfe around his face any witnesses who might have saw him could not be able to tell who it was,much like that rapist from cambridge i think it was,would cycle away from the scenes wearing a blonde ladies wig