My dd is six months old, really enjoys bathtime and is wanting to stay in longer now. I was considering buying a bath seat because it makes my back ache holding on to her and bending down. Has anyone used one, if so do you think they are appropriate for her agegroup? I don't want to buy one and then realise I have wasted my money, or onlyn use it for a few weeks. She cannot sit up unaided yet, are they okay to use when she is able to sit? Any advice would be much appreciated