I think you might have some confusion.
It is (generally) permissible to connect a Solar PV system to the UK grid on a single phase, so long as the output is limited to 16A (at 230V = 3.68kWp) - this is done by various parameters in the inverter that manage the grid connection and synchrisation (actual grid voltage and actual grid frequency)
Solar Panels are DC generators and as such will always generate current in one direction, fit two panels back to back and they will cancel each other out based on voltage.
The chemical and physical nature of the way a PV silicon wafer panels generates electricity means that they are inherently a current llimiting device. see here :
Theory of solar cells - Wikipedia, the free encyclopedia here
Solar cell - Wikipedia, the free encyclopedia and here:
Photovoltaics - Wikipedia, the free encyclopedia
The physical construction of the PV panels is why they usually have a recommended maximum voltage rating of 1000V, else the insulation may break down. In theory you could connect lots together to make 2000V however there then may be a signifcant DC leakage due to the various levels of insulation.
So I think you got the '15' Amps from somewhere else.