Upgrading the inverter to newer Generation Type.
Changing the inverter to an "optimised system" using a Solar Edge inverter with optimisers or an SMA Sunny Boy with optimisers, makes every panel work at its optimum output at that instant, so shading moving across one panel (such as a chimney or a tree) doesn't affect the whole system. "Newer generation" inverters like this will improve your system output, especially if there are shading issues at certain times of the day, or season. The SMA system uses Tigo optimisers to acheive the same result.
You may already have a solar PV system of say 4kwp, which will meet your needs for eight months of the year, but extending it to say, 6kwp, could possibly achieve 10 months coverage. Then adding storage will make much more use of your own generated energy. It is well worth increasing the size of smaller systems to extend the self sufficiency period earlier into the spring and later into the autumn. Installing an east or west facing system - you could have another roof covered with panels to extend the day length self sufficiency period, more energy in early morning and late afternoon when you are likely to be using it. These days with the Feed in Tariff being much lower it makes much more sense to target your own energy consumption by adding east or west facing panels, or south facing panels at a much steeper angle to gain more in the winter.
Updating the inverter system, controls or adding monitoring will help ensure your system is operating at its full potential. Monitoring can be done right down to individual panels with Solar Edge inverters and optimisers, whole system output and building consumption can be monitored via interface systems such as the SMA Sunny Portal and Solar Edge monitoring portals. Separate optimisers from SMA-Tigo, can be fitted to any PV system either to monitor panel output or just optimise panel output.