HBB for 4.8 year old that will last?

[dandelionsRflowers]

My dd is 4.8 and has almost reached 18kg and still in her Maxi Cosi Priori XP. Most of her friends have been in HBB for ages and are moving on to backless ones now. I looked at HBB's ages ago and narrowed it down to the Maxi Cosi Rodi and Britax Kidfix. I fully intend dd to be in the seat for as long as she needs to be so willing to pay for a good seat. I can't decide on what one to get and would like a bit of advice as to good and bad points about the seats.

Concord transformer xt. Excellent at size adapting ( up and out) and great side protection. Also will slightly recline if you are planning any long/ late journeys so can sleep slightly easier

I have just bought a Britax Kidfix for my DD1 who is 5.

DS is 8 tomorrow, and is taller than average and of a 'normal' build, he fits in it fine too and looks comfy. He's 131cm tall, so only 4cm off not needing a car seat any more, and the Kidfix will easily acommodate those extra 4cm.

Op we have just moved dd from maxi cosi pearl /priori (dp car) and today we looked at both of the ones you mention. I like the idea of the isofix still. Only just fitted the Britax one ....it was on offer in Halfords. Seems fine.