I'm not surprised at the cost of most of those, the Slann is a big monster-sized model so was always going to be around £40- £60, the Saurus are now priced as seems to be standard for boxes of 10 infantry, the Krox have the same pricing as the Gloomspite Stone Trolls, and the dull-Jurassic-World-Velociraptor riders are Monstrous Cavalry so were certainly going to cost over £30.
I honestly thought the Salamander was the worst offender, £32.50 for one squat, middling-size Monstrous Beast and three small handlers is far too much, especially without options for a Razordon, though I will also agree the Battle Standard Bearer is also too much. It was already too much of a price hike to see character models reach £20 when the very first plastic characters only cost half that when they arrived on the GW model scene, and now they're approaching £30. GW are taking the mickey ever more nowadays.
I'll have to see if I can convert a BSB from the bitz left over from the Oldblood on Carnosaur. I'm not paying what was once the cost for 10-20 troop box sets for a single foot character. As for the other models I was interested in, the Slann and Kroxigors, I will have to see if I can find those on discount to at least do as much as I can to ease the pain on the wallet.