Thank you, I am still googling and reading to understand most of the reply but I can see that having a second CN for the EV charger seems to be a normal thing.
FYI, the EO Mini Pro 2 installation includes a "Garo earthing device" which they say mitigates the need for earth rods. The EO Mini Pro 2 was only officially released on their website last week.
Every installation tends to be a bit different, depending on the easiest and safest way to make the connection from the incoming supply to the charge point location (and, BTW, the bit on the wall isn't a charger, the charger and it's associated control circuitry is all built in to the car). Connecting to the tails (the heavy cables that run from the meter to the consumer unit) is often the safest and most convenient way to connect a charge point, because the charge point will draw a high current for several hours, so will probably be far and away the highest load within the whole installation, because the charge point has specific protection requirements that exceed those for the rest of a domestic installation and because it's easier to terminate the hefty cable that a charge point needs in a separate metal enclosure.
The protection requirements fall into three categories. First, there is the normal overcurrent protection required to protect the cable that supplies the charge point. This can be by a fuse or circuit breaker. Secondly, there is a requirement to protect the installation from the risk of electric shock in the event of insulation damage or similar, something that's provided by residual current protection, and finally there is the slightly unusual requirement, that applies to any electrical installation that includes extraneous conductive parts located where someone may touch them whilst in contact with the local earth. This latter requirement applies to supplies feeding caravans, metal framed greenhouses, metal sheds, as well as electric vehicle charge points.
The over current and earth leakage protection is fairly straightforward, although the latter needs to be DC tolerant, because there is a DC component in the signalling protocol between the charge point and the charger, hence the statement from EO that they include this. The protection from electric shock from the extraneous conductive parts, i.e. the metal car body, that's insulated from local earth by the tyres, comes about because most houses have the protective earth (PE) provided by the incoming cable from the local grid, often with the neutral being the protective earth, what's called a Protective Earth and Neutral, or PEN, conductor. The protective earth conductors that are connected to the earth pins on all the outlets are, in reality, connected to the neutral terminal at the incoming supply. This means that there is often no local earth, as such. If the neutral conductor in the cable supplying the installation was to go open circuit, say from storm damage, or someone working carelessly in the road, then what can happen is that the line conductor will supply current through the appliances in the house that are connected and so raise the voltage of the neutral, and protective earth, conductors in the house to line potential, typically around 240 VAC.
Inside the house this doesn't matter, as the metalwork or the taps etc will be bonded to the same potential (which is why those bonding wires to pipes etc are called equipotential bonding), and the floor of the house will probably be a reasonable insulator, so there's little risk of shock. Outside, it's very different, as any "earthed" metalwork, like the car body, may now be sitting at a lethal voltage. It would be easy for someone to have their feet on the ground and also touch the car metalwork, with possibly lethal consequences. This is why there is a need to either connect the charge point, and hence car bodywork, to local earth potential, with an earth electrode, and suitable RCD to kill the power if there is any earth leakage, or have some device that can sense an open PEN fault and disconnect not just the live conductors, line and neutral, but also the PE conductor, so that there is no chance that the car bodywork could be at a lethal touch voltage.
There are one or two devices that can provide this open PEN protection, the matt-e O-PEN is perhaps the best known. I'm not familiar with a Garo product that does this, but Garo make some decent protective devices so this may be a new product I've not yet seen. Also, some newer charge points have built in open PEN protection, I believe. The cheapest solution is an earth electrode, though, if one can be positioned close to where the car will be when charging. An earth electrode, cable clamp, and ground termination box is about £20, so a lot cheaper than an O-PEN box.
If the above isn't clear, feel free to come back with questions.