6.4.1 Separate development/test and production environments, what is an acceptable way to deploy to the production environment?

Suppose developers merge php5 source code modules (essentially a set of files in a folder) directly from development machines to the live environment via a samba share (turned on only for the duration of the transfer). The team consists of 3 DevOps that have shared responsibility for server and network administration (i.e. to avoid deployment bottlenecks and have someone to cover when others are on leave). Live web server is on a different network than the development network. The live server is in a secure data centre and the development machines are in a head office. The two networks are connected via VPN. Firefalls restrict samba access to only the development IPs.