LONDON — If last season Simone Rocha lifted us up to the heavens, this time around she described her collection as “grounding” and “earthy.” But there was nothing down to Earth about the grandeur of Central Westminster Hall, complete with a giant organ, and the impressive collection that Rocha sent out. Going back to her Irish roots, the designer found inspiration in the harvest festival of Lughnasadh, hence why puffed-out dresses…