So this where I'm up to thus far.
There is a Metering Coordinator, independent of the energy retailer and the network distributor and has overall responsibility for appointing metering service providers and making sure that metering installations are provided, installed and maintained in accordance with the National Electricity Rules. So AGL is my retailer, SAPN are my distributor, and Intellihub are the metering co-ordinator. AGL basically work with them to receive metering data, do installations and investigations.
As far as I am aware, initial tariff types for SA are all set by SA Power Networks whether they are responsible for the meters or not, in this case the move towards smart meters to all be controlled load in SA, and meters are programmed to reflect those tariff types. The Customer Support person I spoke to appeared to have no understanding of any of this, including SAPN's responsibilities.
So AGL should be able to provide information on how to read these meters, but if my experience (and that of others too) is anything to go by the people in their Resolution Centre can't help because they have NO information on these meters (even though they're supposed to have it). Intellihub are responsible for the programming of these meters through their Metering Co-ordinator, and therefore providing relevant information,but apparently aren't interested in providing help to customers (even though their website proclaims customer assistance as one of their "Values"). I shall refrain from using the language I feel is necessary to describe this "system", the information is apparently out there but you have to know the right questions to ask to find it and to do that you need to know how the system works first to know the questions to ask!
Now to the meter itself (E355), every reference I've found about it so far eventually refers back to Australia in some way so it appears to me that it is designed specifically for Australia (for Intellihub?), which could account for the lack of information on the L&G website(s). I could be wrong on this but I've found nothing so far to indicate that I am. One reference mentioned that it was designed to allow for "disaggregation", which is the ability of the power company to analyse the data from it to determine just what type of appliances you are using and when. This is referred to in the industry as NILM - Non-Intrusive Load Monitoring. I suspect it also provides the ability to remotely shut off your power, and possibly solar export as well. If my assumption is correct about their manufacture then it's likely there is NO user manual for these meters as that would be the responsibility of Intellihub and so far they have shown a callous disregard for customer requests for information.
My Controlled Load times for the smart meter are 11:30 PM- 6:30 AM, and 9:30AM-3:30PM. The second figure is interesting as I'm sure my previous meter only had a 2-hour mid-afternoon slot. Other than having some solar panels my "installation" would have to be considered pretty ordinary, so I suspect these times are likely to be pretty standard for most people but it could vary depending on individual household installations.
What a debacle.
