Hey Tall Chris
Sorry for slow reply – just getting a chance to have a proper look now. Many thanks for the pointers, it helped nudge me into finally finding where to edit it. Going to the home page in WPAdmin then selecting Appearance>Theme options>Slider revealed where those specific photos could be edited.
Having a quick scan through the LayerSlider documentation they mentioned it was sometimes bundled for free with specific themes hence why I had no plugin option to find and edit from there.
Thanks again
Ross
