230V line to line a single phase?

Yes. 230V line to line is considered single phase power. The 115v half part of that is called split phase. It should not be called two phase, as it is one phase that has been center tapped and grounded at the neutral point - it is still one phase power.

230 V is the standard nominal voltage for residences in Europe. 230 V is the line-to-neutral voltage (phase voltage). Low-voltage distribution is by three-phase, four-wire, system with a nominal line voltage of 400 V and a nominal phase voltage of 230 V.