AndreGreyling

Yes, you are partially correct. To quote my friend Google: "Partial shading of one panel in a series string significantly reduces the overall power output of the entire string. The shaded panel acts as a bottleneck, limiting the current flow for all panels in the series, causing a substantial drop in voltage and consequently, power generation. While the string doesn't completely fail, the output can be drastically reduced, potentially to near zero, depending on the severity of the shading"
The partial shading effect on a single panel can, however, be partially addressed by using so-called bypass diodes (factory installed in many modern PV panels), but even so, I believe that some "throttling" of the unshaded panels still takes place.
Another, often overlooked, negative side effect of shading is that localised "hot spots" can occur in shaded areas of the PV panels, and this can over time damage the panels, leading to premature failure. This is not serious if it occurs whilst the sun is not fully bright (early mornings or late afternoons), but is more problematic when the PV panels are producing near peak power during the middle of the day.

I have 6 on one string and 4 on another
The 6 are 3 x 2, facing east, north and west. Highest voltage I have seen is 228 volts
The 4 are 2 x 2 and can reach 185 volts. Both face west

I would second the HA + Kellerza method. Near instant readings and if you can depending on your batteries pull those in as well to HA from its BMS system.
You will be able to monitor much more in detail and setup so many custom notifications. It is a bit of work but worth the time and effort.

And yes I'm aware to the 2 issues on my batteries and waiting on the manufacture/installer regarding repairs/warranty.

Yes, you can use Home Assistant. Search on the forum you will get a lot of hits for "how to"

👍

Protractor with spirit level? Otherwise just a plain protractor and eyeball it?

Or simply download an App such as Clinometer onto your smartphone (it's free...), then place the side edge of the phone onto the panel and just read off the angle of inclination. You could even get a close approximation by just aiming across the edge of the phone held to just see the surface of a panel whilst standing on the ground.

Arcsin(h/l)=a
Where
h is height at top of panel
l is length of panel
a is the angle with the horizontal plane

30 deg year-round average
34 deg Latitude (annual optimum) Balanced yearly performance
45–50 deg winter-focused maximizes winter yield, reduces summer peak slightly
15–20 deg summer-focused more energy in summer, less in winter

Cape Town Latitude: Approximately 34 deg South. Best Tilt Angle for Winter (North-facing panels in Cape Town) Winter-optimal tilt = latitude + 10 deg to 15 deg So: 34 deg + 10 deg to 15 deg = 44 deg to 49 deg.

Rather place the sticker details of the 545W and proposed 550W panels.
The reason is that if the 550W panels have a lower current and you place them in series with the current 5 it might throttle the whole string. If the current is higher then no problem.