bellany - DD1 is 4 1/2, put her on the scales yesterday to make sure and she's just on 16kgs...yes I'm paranoid!! She does reach the shoulder markers, DD1 LOVES her new cup holders, and I'm glad I chose the hi-liner as it has the middle clip to clip to the sash belt which is kinda like a harness, so from your post and the installers recommendation think I'm ok without using the harness. Thanks heaps for your input I'm paranoid and wanted advice from other mums!

HotI - I think so. He said if the harness is inbuilt into the car seat it's all fine and good but if it's added onto the seat and not inbuilt that's where it can be more harm than good as it's another element-kinda....that's how I understood what he was saying!