Original Modern Skin
 

Is this available for download from the site ?

I decided to try out some custom skins this afternoon after reading that you could press "Switch" to return to the default but now I'm stuck not knowing how to navigate to this.

I had expected to find a List of downloaded (and the original) skins to scroll through and select from but the downloads just seem to replace each other and I don't know how to access options.

Right click -> Options -> Skins should do it.
Or Alt+S

Oh thank you so much - I was completely at a loss as to what to do without you.

Thanks for putting my tracks back on track.