That's good - with solar if you know what you have and how to use it you can make the best and most efficient use of your geyser and save a lot on electricity, if not then honestly the geyser is a waste.
Back feeding is a huge problem especially in multistorey buildings.
I am working on my daughter's hot water pipes st the moment and using the opportunity to install non return valves on the cold water line as well as a stop cock on the hot water line from the geyser for the times when you want to repair taps
Yes I know what the regs say and so what the regs are stupid.