Famous pics.
Yes they are, largely because of the Conan Doyle connection. I'm guessing they will fetch a lot more than £2K. Lots of photos taken back then. In this case it's not so much the subject matter of the photos, but the actions they prompted from well known people that makes them famous.
Funny things with antiquities. As once related to me, you can set a 12 lb. iron ball on a desk and at current scrap value, it's worth $3-4.
Place a piece of paper next to it establishing provenance that it was recovered at the Gettysburg Battlefield and that same iron ball is now worth around $200.
Place a piece of paper next to it establishing a rock solid provenance that it is the very cannonball that removed General Sickle's leg at the Battle of Gettysburg, and you've raised the value into the hundreds of thousands of dollars.