Damsel in distress

[5MUG]

We have a 5L Chimaera and now have an addition to our family who is now 5 months old. I am trying to persuade my husband to change from the Chimaera to a Cerbera. His main concerns I think are: unreliability and its not convertible (can't do much about that). Has anyone been in the same position? Any advice re which model etc?

[5MUG]

Thank you all. I'll keep you posted on developments. Anyone know the actual name (model) of the Britax seat that fits?