Just bought one plus 2000 boots points today only which is £20 in my boots card. So the car seat actually cost £99.
I'd save the extra £30 and go with Stages over Every Stage anyway as it has a deeper seat so more legroom. If you need to use it ff in harnessed mode the Every Stage didn't get good safety reviews compared to the Stages. Plus when the time comes to use as a hbb both seats are bulky and hard to plug in compared to a dedicated hbb so, although useful as a spare/occasional seat, not great to use on a day to day basis and much better to spend that £30 on a dedicated hbb.
I think that's Joie Stages, which doesn't have the ability for Group 3. See link: https://www.halfords.com/kids-zone/car-seats/baby-car-seats/joie-stages-0--1-2-child-car-seat They currently do not have the Every Stage in Halfords.
Got a link?
Under £90 in Halfords.