Do I really need one or would a baby sling be enough? I have purchased a Baby Bjorn Synergy carrier (with lumbar support). Just wondering if it is practical to use this as my primary carrier as I have a very small car (two door). After fitting the baby capsule in, it doesn't leave much space for a pram (or anything else!). I also have a very small frame (bodywise) and find pushing prams quite cumbersome Please help as I really am quite lost!TIA