The British first edition came with a manual, a precautions booklet, a Wii code flyer, a Wii catalog, and the same disc as all the other PAL first editions.
The first edition has a red Nintendo logo on the front, and came with a red and black disc. The second British edition has a white Nintendo logo and a new barcode. The third edition has identical box art to the second edition, but a new disc label in multiple colors.
1. Front
2. Back
3. Disc
Thanks to OGDB (images 1-2).