Found my style eventually - it had completely wiped the style and I had to set it up again with the right layers.
Note to self - this is how to do it if it happens again:
Pick Flexible Squares Tokio Hotel (#31828633) as the style
Language : English UK
Layout: Flexible Squares (Tokio Hotel) (#1112942)
Theme: Tokio Hotel Header (#16072590)
User: Auto-generated Customizations (#16072856)