[R] New line operator in mtext

[Steve Murray]

Thanks again for a very useful comment. That seems to have separated the text and put it onto separate lines.

However, whilst this results in the text being centralised in relation to the axis, it means that the lower line is left-justified in relation to the upper line, rather than being centralised.

How do I go about centralising the lower line in relation to the upper line, whilst keeping it central to the axis?

Many thanks again,

Steve