OK so finally I've found other people who have experienced the same issue. It hadn't occurred to me to search for TSX owners and their opinions on the seats. Check here and scroll down til you see the single image (composed of three other images) of different car seats with crudely drawn ms paint lines over them. Read the post, this person is describing EXACTLY what I'm experiencing. It is a three year old thread but at least it's reassured me that it's not something I'm doing. Next option is to look around to see if I can get a different front seat installed. Failing that I think I'll be searching for a new car.