Ok, so I’m part way through solving the font issue. Fixing my grandmas laptop and its in front of me (and its old, the horror of opening my site in i.e. 6 purely out of interest is for an entirely different thread)
I’ve changed the default font for PC to Arial as this seems to be much more optimised compared to Museo Sans which was previously being pulled form TypeKit. On Mac I’ve opted for Helvetica Neue, however if a retina display is being used then Museo Sans.
Much more readable don’t you think?