Ria was a great host, showing us around bookshops I had never been to even after having lived in London for 13 years!
I liked the variety of bookshops we went to - one was specialised on first editions/collectibles, one was a LGBTQ shop, one had brand new books but only a fraction of the price.
One thing was around the timing: 10-15 minutes in a bookshop isn't a lot, especially with a group of bookworms - so you might want to note the shops you want to go back to and spend more time after the tour.
We finished the tour 30 minutes later than the original timing - which was fine, but best to not schedule another activity straight after this one!
I particularly enjoyed the guide Ria has sent in advance, which included a little bit of background on each of the bookshops, as well as some "speed book dating questions".