We can now put some approximate dates on these thanks to research by reader 'Greyfox'.
1. No printed information on card.
2, 3 & 4. Probably 1880-87.
5. Database of London photographers has many addresses for a Myles Garner, but none at the location on the card. His son, also William Myles Garner, was also a photographer. But none of the traced addresses matches the Notting Hill Gate shown on the photo.
6. A Simmons, 1882-1888. (Before he opened a second studio.)
7. No information on card.