With solar, it is not what the solar produces, it is how electric is bought and sold which makes it worthwhile or not.
In the early days some countries bought and sold at same price, so no need for a battery. The need for a battery is hinged around the off-peak tariffs, and the difference between selling price and buying price.
So over the years, the advantage/disadvantage of energy storage has changed. When economy 7 first came out, the overnight tariff was so cheap, it did not matter that energy was wasted as it heated the home at the wrong time, there was still a gain monitory wise.
The same with the likes of the iboost+ and using solar to heat water, the unit still works well, but the tariffs mean it no longer makes monitory sense.
I have been surprised when reading the forums, how many people even with professionally fitted solar, are not paid for export. But for 20 months I fought with British Gas to try and get payment for export, and failed, then moved to Octopus and all sorted within 2 weeks.
Basic fact was British Gas were giving me the run around, I needed to apply to the DNO for a second MPAN number, but British Gas were telling me I had filled in their forms in the wrong format. Hindsight, it was due to British Gas delay in fitting a smart meter, if it had been fitted before solar, then the solar company would have done the paperwork, but it was fitted 4 months after the solar, so it was really down to British Gas.
However, the point is, it is tariff dependent, and what is or is not worthwhile, all depends on tariffs. And even then, the tariff advertised as being for solar, for most people as not as good as the tariff advertised as being for an EV.
But with only 800 watt, what tariff will help is a problem. Until I had solar a year I had no idea what tariff would work out best for me, and since a added a second battery, it was two years before I could really work things out as to which tariff was best for me.
And when the tariffs changed, so did how much solar save change. Solar is a leap of faith, as tariffs are likely to change many times during its life.
It seems Octopus


will be paying for export, so this really changes the question as it if it is all worthwhile.