For information. Here is an official reply I received (finally) received from British Gas about the optical probe port on the Landis + Gyr E470 Zigbee meter that is being installed by them as part of the smart meter rollout.
For reasons of security the optical probe system is closed after the point of manufacture. It doesn’t pass readings via the internal mechanism and therefore no information can be gained from it. The optical port can’t be opened remotely so unfortunately this is not an option. Also each meter manufacturer creates their own internal software and are unlikely to make it accessible to the general population. We know that Landis and Gyr won’t allow their version of software out and British Gas don’t have access to it.
So don’t waste time like I did trying to read from it. I guess its back to pulse counting.