I’ve recently purchased and had fitted, a Joie i-Gemm car seat and isofix base from mothercare. However it seems very unstable; rattling and lifting up from the base even when the safety indicators are green. I’ve been back to mothercare today to check it’s been installed correctly and they said yes but I’m worried about whether or not it’ll be safe enough to use when my first born arrives next month. Anyone else had the same problem?