Yes, that's what I've done if you look at my opening post. But that removes font boosting from everything. I just wondered if there was a way to keep font boosting on and apply it to the Toolset Grid/Columns (which removes it by default).
I don't think it's theme related - it's a mobile browser feature.
Issue not really resolved but probably not Toolset's problem (though it does affect the display in mobile browsers). All the solutions were the same as I'd got in my opening post i.e. removing font boosting, I wanted font boosting to be APPLIED, not removed 🙂