I had solar panels (5kWp) and battery (13.5kWh) installed on 1st July and have paid only standing charges since then, saving approximately £80 in 6 weeks.  I've exported 380kWh to the grid so far but not been paid for it (waiting for the DNO to get their finger out!), nominally worth £57.

Come winter, I'll be playing tunes on the battery, charging at cheaper overnight rates, so improving on what I achieved last winter without a battery.

We don't get paid. So will talk about my case.

Without a battery anything more than 3.2kW you end up exporting quite a bit in summer. Unless you dump to immersion and hot water. Even in NE Scotland and quite a bit of shade we didn't really pay for hot water in summer.

We then added another 3.6kW PV and 13.5kW battery, ASHP and moved to E7.

According to our weekly reports our summer average cost per kWh used is about 4p and Jan Dec was 20p kWh driving a heat pump (we had 2 weeks at -9 also).

Battery is best way to self consume. We still use immersion diverter. Last cylinder heat was yesterday at 4am, next one will be tomorrow morning (so 48hrs). Which is good as we have had a poor solar day today, so didn't use the battery to heat DHW. We still import, mainly due to a pretty poor summer, on average 4 to 5kWh. But that includes running ASHP on cooling mode, MVHR, sewage treatment plant fan our base load is around 17kWh.