There's a fb group called "car seat safety uk". If you pop your requirements in there the admins will provide you with recommendations, really useful group. We got our car seat through one of the admin recommendations and it's fantastic 😊 x
Joie stages!! Doesn’t have isofix or tethers like most car seats and it’s actually a safe recommended one! It uses a seatbelt similar to how an infant carrier works and it’s only £100
https://www.argos.co.uk/product/9492956?clickSR=slp:term:car%20seat:6:83:1. We just bought this one. It’s really quick to install and it’ll last ☺️