Great to see you in the Community @MarkH! Thank you for your question. I am sending this over as a ticket to support as I expect they will need to investigate this with the webpage url you’ve set up. 

Thanks Ryanne.

We managed to bodge it with some hacky CSS so the left and right columns stack vertically (sketchy code below for anyone else running into this issue) so it’s OK for now. But it’s not really an ideal solution as it doesn’t look great.

It would be great to see if support have a better solution though thanks!

/* mobile lightbox fix */

/* left image */
@media screen and (max-width: 767px) {
    #bynder-widget-lightbox>.bynder-widget-figure>div.bynder-widget-table-wrapper>.bynder-widget-cell-wrapper {
        height: auto!important;
      }
    }

/* right detail panel */
@media screen and (max-width: 767px) {
      #bynder-widget-lightbox>.bynder-widget-figure>div.bynder-widget-table-wrapper>.bynder-widget-cell-wrapper, #bynder-widget-lightbox>.bynder-widget-figure>.bynder-widget-table-wrapper>.bynder-widget-overlay-detail {
        margin-top: 50px!important;
        margin-bottom: 0px!important;
        display: block!important;
        width: 100%!important;
        height: 150px!important;
        }
    }