As a comparison these are my figures for a 6kw system for the month of June
solar 704 kwh
exported 433
grid consumption 7.9
Battery provided 92
Load was 213
What is important to note is the solar production does not reflect what could have been produced because when export is above 5Kw and battery is full and not consuming then inverter throttles back what it needs from solar if nowhere for juice to go.
My export is on the Octopus variable 1/2 hour rate and last month average was about 17p a unit in March it was 22p reflecting less power being generated nationally.
This last month my account was credited with £75 being the excess of export over consumption / standing charge