further update, today is another good example of a coldish but very sunny day,
Thats my general readings, so on the leaving water temps the 2 spikes are hot water cycles.
Today, the PID controller has kept it sat 3 degrees lower for a nice long steady period due to solar gain etc. Seems to be running very well, suspect today will likely 8 to 9kw of energy used across a 24h period which for an Octopus installed Daikin 8kw is probably the best i can hope for.